There is a ton of psychology and a great deal that has been written about both those who enjoy this and those who inflict this upon others.
Posted this in another thread.
Check out this blog post.
What do you guys think of this photo and caption/story?
Hunt Down and Expose Small Cocks: Sauna showoff.. This is what every hung guy enjoys doing when he sees a hot guy like him in sauna hiding his small penis with his towel....
your sauna story reminded me of this fantasy
Ouch! Musta hurt.i was told, " its so small" by some black dude in a sexual situation between 3 guys in a public restroom at UCLA.