Aaaaaaaaaaahahahaha!!! Aaaahahahahahaha!!!!

Sorry, but it had to be done.

I've occasionaly thought my shorts were too tight in that area, but never experienced a reduction in size. Do you get worried when you get into cold water? I'm guessing not, but it still is something that makes it temporarily go down in size. As long as it comes back with reasonable time and doesn't hurt then I personally don't see it should be much of a problem.