I regularly attend a festival with a clothing optional policy.
Turns out that between the sunburn, the mosquitoes and the cool evenings, clothing is actually a good idea, and most people "opt" for it most of the time.
But quite a few people do go topless or naked at least some of the time, and a strange phenomenon can be observed. When in public, and when engaged in normal social activity, as the amount of clothing over an erogenous zone decreases, the appearance of intentional sexiness increases; but only up to the point where the clothing disappears entirely, then the appearance of intentional sexiness crashes to zero.
Unless you're doing this in private, of course.
