I don't know how many will respond, but a lot of the really big guys on here have, at one time or another, been made fun of. Unless they run into a really hung guy, I doubt how many average guys were made fun of. Most guys are average, whether we want to believe that, or not. A lot of it isn't malicious ridicule for big guys, it is more of a reputation thing. It's being called, horse, pony boy, king dong, and crap like that, and others wanting to see if it's true. That can get tiresome, as well. I remember my Grandad telling about making fun of a really large guy he was in the Army with.

Anything that is outside of what's common in your group will bring ridicule.
It may be skin color, height, religion, nationality, glasses, etc. That's just the way people are. I have gotten some off comments because of my Norse heritage. One guy said "yeah, those Vikings like to hit people over the head with a mace". I didn't take offense to it, but some would have. I have also been called, " hot rod, hoss, horse, big foot, and cat in the hat".
The "cat in the hat" came from my wearing a cap that had "Cat Diesel Power" on it, for years. None of that really bothered me either.

Like my Dad, and Grandad told me, if you get picked at for being taller, bigger, stronger, or smarter, those doing the picking are just jealous.
Even so it's still annoying, at times. I don't pay any attention to anything anybody says anymore. Unless it gets physically threatening, I ignore it.

To answer your question directly, yes, I was picked at over penis size.
This happened around the age of puberty. Those who were calling me small were ahead of me in puberty. Some of them for good reason, they were older than I was by a year or even two. I never heard any comments after I got to high school. I guess things evened out.