I checked out a self-defense course at my university, and for one of the techniques I was paired with a female. The attack was a torso grab from behind (bear hug type, pinning the arms to the body). This female was quite well-endowed, so I was nervous about 'getting too close for comfort' - I didn't want to appear sleazy - but she was so big in that area, that it would be hard not to touch them.
So, anyway, trying to be P.C. (which I'm normally against), I grabbed her high around the upper chest and shoulders. She got irritated and said, "That is not realistic, you're going to have to grab me lower," then *she* took my hands and placed them squarely (or rather roundly) on her bosom, and told me to squeeze tightly.
It was a benefit for me for obvious reasons
but it was also a benefit for her - she had enough sense to know that if she is going to practice proper technique, there has to be a proper attack to respond to.
Intimate contact really is unavoidable in a grappling situation, but I agree that - just to make everyone more comfortable - there has to be trust and consent involved.