[Sheba]

You'd better make sure to wear lint-free clothing, too, and to shave off your pubic hairs---otherwise the hair and fiber analysis that's part of a standard rape kit will find evidence.

Also if you sweat on her too much, you will leave traces of DNA behind.

If you do her missionary, I recommend contacts in case she remembers your eye color.

To be extra-safe you could wear shoes a size too small with lifts in them---that way the police end up looking for someone taller than you who wears a smaller shoe. (if you leave shoeprints.)