Judgment unanimously affirmed. Memorandum: Defendant was convicted following a jury trial of rape in the first degree (Penal Law § 130.35) of a prostitute and known drug abuser. On appeal, defendant contends that County Court erred by precluding him from offering the testimony of lay witnesses concerning the effect of cocaine on the victim. We disagree. Defendant failed to make an offer of proof clearly and unambiguously indicating the relevancy of the testimony and what he intended to prove by its introduction (see, People v Williams, 6 N.Y.2d 18, 23, cert denied 361 U.S. 920, rearg denied 10 N.Y.2d 1011; People v Baxter, 177 A.D.2d 1003, lv denied 79 N.Y.2d 943). In any event, County Court did not abuse its discretion by curtailing exploration of such a collateral matter (see, People v Davis, 43 N.Y.2d 17, 27, cert denied 435 U.S. 998).