Hmm. Is there any way that you can arrange yourself so that you're not protruding? I know it's possible with some people's anatomy, but not with others.
In lieu of that, I would consider going to buy the smallest athletic cup that you can find. That would provide a gap between you and anything else, but may not be the most comfortable thing to wear, especially with trying to pack over top of it. I imagine it would take some practice to get it to look right.