Why men like to wear panties?

What the hell is wrong with you? Nothing! Your penis is an "erogenous zone", which is a fancy way of saying that when it's stimulated, you get turned on. Most of us have lots of erogenous zones -- that's why kissing feels good -- and different kinds of stimulation turn them on. So the simple answer is "because it feels good." Don't worry about it. By the way, whenever someone asks "why", it's a good idea to think about what would change if you knew the answer.