**The following contains adult terms and situations, readers beware.** I believe, and this is purely speculation, that guys DON'T in fact shrink in water. I've been swimming, wading, bathing, and many other things involving water. As far as I know I've been 5'10" the whole time. As for mens' penises (penis', penii), that may be a different story. I think the "shrinkage" you speak of normally only happens in COLD water. The colder the water the more significant the shrinkage. We know that the cold makes molecules move less and group together, subsequently shrinking whatever the molecules form, even penises. So how can we have sex in hot tubs, pools, etc? First of all, having sex in any water is generally a bad idea. What with germs, chlorine, and other chemicals, its just nasty. Nonetheless, I doubt that "shrinkage" seriously effects the size of erections, or sexual ability. If a man has an abnormally small penis his ability to have sex when his member is "shrunken" may be less. But normally, men can "do it" in hot tubs, pools, bathtubs, and lakes because : 1. Shrinkage isn't really a concern unless the water is cold. Why would you want to have sex in cold water? 2. Shrinkage isn't too much of a concern when erections and sexual intercourse are considered. Trust me.

Shrinkage is caused by cold - not water - and the member in question will still "grow" with a little, um . . . TLC, regardless of the ambient temperature.

The real problem, for me anyway, was not shrinkage, but lack of lube. I would recommend sex after the hot tub.