
404 S.E.2d 6 (1991)
102 N.C. App. 687
STATE of North Carolina
v.
James Henry WOODARD.
No. 9012SC53.
Court of Appeals of North Carolina.
May 7, 1991.
*8 Atty. Gen. Lacy H. Thornburg by Asst. Atty. Gen. G. Lawrence Reeves, Jr., Raleigh, for the State.
Appellate Defender Malcolm Ray Hunter, Jr. by Assistant Appellate Defender Mark D. Montgomery, Raleigh, for defendant.
LEWIS, Judge.
Defendant was indicted on 15 February 1988 for four counts of first degree burglary, four counts of first degree rape, and eight counts of first degree sexual offense. Defendant was convicted of all charges and sentenced to two consecutive life sentences. Defendant appeals.

I. Evidence of Defendant Woodard's Sexual Habits.
Defendant first assigns as error the denial of his motion in limine to restrict the State's cross-examination of the defendant regarding an adulterous relationship he had with Ms. Thompson. On cross-examination, the defendant admitted that he knew Ms. Thompson, but denied ever having any sort of sexual relationship with her. The State then submitted to the defendant *9 several "love" letters which impeached the defendant's prior denial of involvement with Ms. Thompson in an affair. The defendant denied any knowledge of the letters which were found in his desk drawer at his office, but nonetheless was required to read them to the jury. The defendant cites Rules of Evid., Rule 608(b) which restricts cross-examination using prior acts of misconduct to those acts which relate to truthfulness or untruthfulness. N.C.G.S. § 8C-1, Rule 608. We agree. Rule 608(b) limits the State in its inquiry to types of the defendant's misconduct, which involve truthfulness or untruthfulness. We note that Rule 608(b) does not allow the use of extrinsic evidence concerning that misconduct to impeach a witness. Adultery is not the type of misconduct which falls under Rule 608(b). See State v. Morgan, 315 N.C. 626, 634, 340 S.E.2d 84, 90 (1986).
The prosecution cross-examined the defendant concerning his affair before the defendant put character witnesses on the stand to testify as to his law-abidingness. The trial court erred in allowing the prosecution to ask the defendant about his adultery before the defendant put his witness on the stand. N.C.G.S. § 8C-1, Rule 404(a)(1) states that as a general rule evidence of a person's character is not admissible to prove that a person acted in conformity with that character. However, evidence of a person's character is admissible if the accused offers evidence of a pertinent trait or the prosecution offers evidence to rebut the same. N.C.G.S. § 8C-1, Rule 404(a)(1).
Here, it was only proper for the prosecution to refer to the defendant's illegal adulterous affair in order to rebut the defendant's contention that James Woodard was a law-abiding citizen. Therefore, we find that the trial court erred in allowing the prosecution to cross-examine the defendant concerning the adulterous affair and to require the defendant to read the "love" letters concerning the affair on cross-examination. Defendant also contends that the trial court erred in allowing Ms. Thompson to testify regarding the affair. Here, the evidence could be used because by then the defendant had presented evidence that James Woodard was a law-abiding citizen. N.C.G.S. § 8C-1, Rule 404(a)(1).
As to the evidence of the adulterous relationship which the court admitted, we hold that the error is harmless and that there is no "reasonable possibility that, had the error[s] in question not been committed, a different result would have been reached at trial." N.C.G.S. § 15A-1443(a).
The defendant further objected to the questions posed by the State on cross-examination regarding the presence of "Sta-hard" cream and pornographic videos and magazines found in the defendant's bedroom. Testimony of the victims indicated that their attacker had difficulty maintaining an erection during the rapes and that the "Johnny Gustud" personality (who supposedly committed the crimes) was a sexual deviant who said he only wanted to make the women he raped "feel good." This character was contrasted to that of James Woodard, who was portrayed as a family man and minister and testified that he did not have problems with impotence.
We hold that the State's inquiry into the defendant's (James Woodard's) use of the "Sta-hard" cream was a proper area for cross-examination to allow the jury to infer, if it chose to, that the defendant did not suffer from a multiple personality disorder. The cream was found in the defendant's home where he, as James Woodard, lived with his wife free of any problems of impotence. If the jury inferred that "James Woodard" owned or used the cream found in his home, this would directly contradict the defendant's theory that James Woodard was a personality separate and distinct from that of Johnny Gustud. The evidence tends to show that Woodard and "Gustud" were not separate personalities but one and the same and Woodard was conscious at the time the crimes were committed and that he was aware of his actions. We find no error as to the admission of the evidence of the cream.
We find that the court erred in admitting the evidence of the pornographic *10 videos and magazines found in the defendant's home. We hold that this error, however, was harmless and would not create a reasonable possibility that the jury would have reached a different result at trial. N.C.G.S. § 15A-1443(a).

II. Problems Arising from the "Appearance" of an Alter Personality at the Close of All of the Evidence.
Defendant next argues that the court "erred in not protecting defendant from prejudice arising out of the conduct of Johnny Gustud." During the charge conference, "Johnny Gustud" made his first "appearance" in the courtroom. Defense counsel made a motion to re-open the evidence in order to allow "Johnny Gustud" to testify. He informed the court that "he" wanted to testify and that this testimony would tend to exculpate the defendant James Woodard. The court refused to re-open the case. At this point, "Johnny Gustud" became very disruptive and eventually had to be taken out of the courtroom and shackled. Defendant now contends that he is entitled to a new trial (1) because the trial court did not re-open the evidence to allow "Gustud" to testify; (2) because the trial court denied the defendant's motion to remove "Gustud" from the courtroom; and (3) because the trial court finished the trial without waiting for "Gustud" to resume the personality of James Woodard. We will address each of these exceptions in turn.
First, we do not find that the trial court erred in refusing to re-open the evidence to allow "Gustud" to testify. Whether or not to re-open the evidence in a case is a matter within the sound discretion of the trial court. State v. Mutakbbic, 317 N.C. 264, 273, 345 S.E.2d 154, 158 (1986). Defense counsel admitted that they had made a tactical decision not to elicit testimony from the "Gustud" personality during its case-in-chief because they feared that it might appear to the jury as a "Hollywood ploy." In fact, the defendant's own witnesses testified that they were capable of "calling out" the "Gustud" personality. The defense attorneys chose not to do this during the trial, and the trial court did not abuse its discretion in refusing to re-open the evidence when "Gustud" appeared.
Likewise, we do not find that the trial court erred in refusing to remove the defendant from the courtroom. The transcript reveals that once he was shackled, the defendant was no longer disruptive. The trial court also could not, as the defense requested, instruct the jury that the person sitting at the defense table was not James Woodard, but instead was Johnny Gustud. If the judge had done so, he would have impermissibly expressed his opinion as to whether the defendant in fact had multiple personalities. We find no error.
Third, the defendant argues that the court should not have continued the trial without his being "present." The "Gustud" personality made it very clear that unless he was allowed to testify, he would not allow the defendant "to come back." We find that under these circumstances, the trial court did not err in proceeding with the trial. There was only one person accused of rape. We find the defendant's presence in the courtroom sufficient. The trial court did not err in proceeding with the trial.

III. Refusal by the Trial Court to Instruct on Involuntary Commitment Proceedings if the Defendant was Found Not Guilty.
In his next assignment of error the defendant argues that the trial court erred in refusing to instruct the jury that if they found him not guilty because of unconsciousness based on a mental disorder, he would be subject to a civil commitment proceeding. The defendant cites no statutory or case law requiring him to instruct the jury about the possibility of the defendant being subjected to involuntary commitment proceedings. In fact, the judge indicated that he was not certain what he would do if the jury returned a verdict finding the defendant not guilty by reason of unconsciousness. Whether the defendant would have been subject to involuntary commitment proceedings at that point was pure speculation. We reject this assignment of error.


*11 IV. Placing the Burden of Persuasion on the Defendant Regarding the Question of Unconsciousness.
Defendant contends that the trial court erred in instructing the jury that the burden of persuasion was on the defendant to show that he was unconscious at the time of the commission of the crimes. The trial court gave the following instruction to the jury:
If the defendant was unable to act voluntarily at the times in question, he would not be guilty of any offense. As to the defense of unconsciousness, or automatism, the burden rests upon the defendant, James Henry Woodard, to establish this defense, not beyond a reasonable doubt, but merely to the satisfaction of the jury.
"Unconsciousness is an affirmative defense and the burden is on the defendant to prove its existence to the satisfaction of the jury." State v. Jerrett, 309 N.C. 239, 265, 307 S.E.2d 339, 353 (1983); State v. Caddell, 287 N.C. 266, 290, 215 S.E.2d 348, 370 (1975). We reject this assignment of error.

V. Testimony that the Defendant "Pretended" to be Asleep.
The defendant excepts to the testimony of Lieutenant Binder, a witness for the State, that while driving "Johnny Gustud" to possible crime scenes, the defendant "pretended" to be asleep and then woke up as "James Woodard." The defendant contends that testimony by Lt. Binder that the defendant "pretended" is an inadmissible opinion and that the trial court erred in overruling the objection. We disagree. N.C.G.S. § 8C-1, Rule 701 allows lay opinions when they are "(a) rationally based on the perception of the witness and (b) helpful to a clear understanding of his testimony or the determination of the fact in issue." We find that Lt. Binder's opinion that the defendant "pretended" to be asleep in the patrol car meets the criterion set forth above. We find no error.

VI. Failure of the Trial Court to Instruct on Second Degree Rape and Second Degree Sexual Offense.
Defendant argues that with regard to one of the victims in the case, the trial court erred in failing to instruct the jury on the offenses of second degree rape and second degree sexual offense, on the grounds that an unloaded gun is not a "deadly weapon." On appeal, the defense adopts a new theory, arguing that there was insufficient evidence that a deadly weapon was used because the victim only testified that she heard a "clicking" noise which could have been a knife or a gun. Rule of Appellate Procedure 10(b)(1) requires that in order to preserve a question for appellate review, the party must state the specific grounds for the ruling the party desires the court to make. N.C.R. App.P. 10(b)(1). Here, counsel stated to the court that he was objecting to the denial of its request for an instruction on second degree rape and second degree sexual offense because he did not believe that an unloaded gun was a "deadly weapon." The defendant may not change his position from that taken at trial to obtain a "steadier mount" on appeal. State v. Benson, 323 N.C. 318, 322, 372 S.E.2d 517, 519 (1988). Defendant never objected or gave any indication that the basis for the request was because the jury could find that the defendant did not use any weapon in the commission of the rape. "The theory upon which a case is tried in the lower court must control in construing the record and determining the validity of the exceptions." State v. Hunter, 305 N.C. 106, 112, 286 S.E.2d 535, 539 (1982). A gun which is used in the commission of rape to threaten the victim into submission, if not known to be unloaded, is an "article which the other person reasonably believes to be a dangerous or deadly weapon" and is sufficient to meet the definition of first degree rape. N.C.G.S. § 14-27.2(a)(2)a; See State v. McKinnon, 306 N.C. 288, 293 S.E.2d 118 (1982). We find no merit to this assignment of error.

VII. Entry of Two Counts of Sexual Offense as to Each Victim.
Each of the four victims testified that the defendant performed cunnilingus *12 on them. For each of the four victims, the trial court instructed the jury on two counts of first degree sexual offense. The defendant appeals because the trial court did not instruct in such a way as to make it clear which of the two alleged sex acts went with the indictment. After reviewing the transcripts we find that there is no basis upon which the jury could have found the defendant guilty of one continuing sex offense. Each of the victims testified to at least two separate sex offenses. We reject this assignment of error.

VIII. Imposition of Two Consecutive Life Sentences.
The defendant contends that the imposition of two consecutive life sentences in this case constitutes cruel and unusual punishment in violation of our State and Federal Constitutions. We disagree. The defendant was convicted of four first-degree burglaries, three first-degree rapes, and eight first-degree sexual offenses. The sentence imposed is authorized under the statutes. We find that the sentence imposed is not disproportionate to the crimes committed.

IX. Conclusion.
For the reasons stated above, we find that the defendant received a fair trial, free of prejudicial error.
No prejudicial error.
ARNOLD and JOHNSON, JJ., concur.
