California Code, Evidence Code - EVID § 1106

(a) In any civil action alleging conduct which constitutes sexual harassment, sexual assault, or sexual battery, opinion evidence, reputation evidence, and evidence of specific instances of the plaintiff's sexual conduct, or any of that evidence, is not admissible by the defendant in order to:

(b) Subdivision (a) does not apply to evidence of the plaintiff's sexual conduct with the alleged perpetrator.

(c) Notwithstanding subdivision (b), in any civil action brought pursuant to Section 1708.5 of the Civil Code involving a minor and an adult as described in Section 1708.5.5 of the Civil Code, evidence of the plaintiff minor's sexual conduct with the defendant adult shall not be admissible to prove consent by the plaintiff or the absence of injury to the plaintiff.

(d) If the plaintiff introduces evidence, including testimony of a witness, or the plaintiff as a witness gives testimony, and the evidence or testimony relates to the plaintiff's sexual conduct, the defendant may cross-examine the witness who gives the testimony and offer relevant evidence limited specifically to the rebuttal of the evidence introduced by the plaintiff or given by the plaintiff.

(e) This section shall not be construed to make inadmissible any evidence offered to attack the credibility of the plaintiff's testimony as to something other than consent or absence of injury as provided in Section 783.