Batman corstume issues. Need a quick fix :P?

For my 21st birthday i'm dressing as Batman for a Superhero themed party. The costume is a onesie type thing and super tight around the crotch region, showing off the manhood. Now if it were just the younger folk it would be fine, but a lot of family and family friends will be there and I don't want them seeing anything below the waist.

Any ideas how to hide it, but still not look ken doll like?