Why do guys brag about their penis size?

haha its freakin both. insecurity definitely, definitely. contest. yep fo sho.

LOL, I don't know how true this really is because the majority of guys have nothing to brag about.

Here's a secret most guys who flaunt at the fact that they have a big penis, don't have a big penis, its the ones who don't mention the fact that they do or don't are the ones that do.

Not really but when guys do they all ways say its like a monster and shit like that its pretty stupid its kinda like girls talking about how big there boobs are or there ass you know

Lol, that's a great one. Um well in todays culture we are expected to be many things. Women are expected to flat stomachs, large breasts, and to be curvy at the same time. With guys it's not as superficial but it's still expected that he will have muscular body. Now it has been apart of popular culture that men need a bigger penis to please his women. You see for guys it's more about pleasing his woman than him having an orgasm. So a larger penis is something that gives ya bragging rights about who can give it better to his girl (ie: guys bragging that they made her scream and such).

Other than that yes it's a contest (testosterone does that) and it's a little bit about insecurity too. Kinda like peacocks displaying there feathers (although it would be so wrong for guys to do that with their penises)

I agree with gravygirl, they probably think we like it, BUT SERIOUSLY WHY DOES IT MATTER?

I think some guys want to show their "Alpha-male" dominance in order to prove they are the best mate for the girl they are interested in. I think the rest are either liars or insecure. Ha ha - sorry guys - no offense!

It is probably their insecurity.

They think we'll like it.

And to be fair I did once date a guy mostly for what I'd heard about his penis. It was a long time ago and I was young and curious.

I've always wondered the same thing.
Ego boost?
Now sure.
They need to realize "bigger" is not necessarily "better"
:]