I gets lots of it on my phonesex line, only sometimes in person....

Its exactly what it sounds like pretty simple...sometimes related to cuckold and bbc fun too...should be pretty easy to find online info...

It falls into a couple categories, strict denial versus guys who are "pathetic" versus guys who like to see you with "a real man" like a personal porno...or guys to like to share

Cheers,
Isabella Crush

WHAT penis???

ohhh, you call THAT a penis? HAHA, that's not a penis! My pinky finger is more of a penis than that. Awww...what do you even do with that little baby peewee worm dick? Are you sure you weren't actually born female and that's just like an overgrown clit? Eeehehehe!
Gosh, it must be so embarrassing when you date a girl and she see's it for the first time and just busts up laughing.
Etc, etc, etc.. it's mostly verbal - just letting the insults fly... just go for it - anything you can think of - can't really go wrong, hehe.

But yes, it's definitely a humilation thing and you have to be into humiliating someone to really get into it.. I love me some real humiliations whores

I think the psychology behind it is that being humiliated/embarrassment is such a strong emotion that it can be used to reach "subspace".

Baby dick!

I recommend doing some of your own research by reading.  50 shades of gray, or BDSM 101 are both great books.  I google ?'s I have instead of asking here on public boards.  Google is your friend.

Everyone has their own personal reasons for their kink.