Check out this post via She-Hulk fan blog Shulkie.com speccifically on Peter David's, 'super-strong vagina thesis':
I think any normal man who would have sex with She-Hulk is courting disaster. I don't care how stiff your stiffy is: She-Hulk's vaginal muscles alone, if she were to orgasm, would be enough to earn you a trip to the E.R. The price of a tumble with She-Hulk being broken bones pales in comparison to the prospect of a broken boner because, yes kids, it can break, and not all the king's horses, men or Viagra will put Humpty back together again. Lambskin Trojans? Forget that. Tony Stark must have used an amored condom. The Invinicible Iron Man Thing.