Is circumstantial evidence of consent sufficient to warrant instruction on the defense of consent?

Even where the defendant does not testify, circumstantial evidence of consent can be sufficient to warrant instruction on this defense. In People v. Anderson (1983) 144 Cal.App.3d 55, 62, 192 Cal.Rptr. 409, the defendant's five-year-old son, who was present during the commission of the alleged rapes, was the sole defense witness. He testified to facts from which it reasonably could be concluded the victims assented to sexual intercourse. The testimony of one of the victims, indicating she did not attempt to escape from the defendant's vehicle when it was stopped at traffic lights, was considered to be additional circumstantial evidence as to the defendant's belief in consent, warranting the instruction. (Ibid.)