How have the courts interpreted jury instructions in a sexual assault case?

Defendant contends the trial court erred by giving certain jury instructions that, although correct statements of law, do not apply to the facts of this case. A trial court should give a requested instruction only when it is supported by substantial evidence. (People v. Marshall (1997) 15 Cal.4th 1, 39.) Theories that are unsupported by the facts should not be presented to the jury. (Id. at pp. 39-40)