A sorority girl. Based on the often true assumption that you cannot get with them unless you've joined a frat and paid to have friends.
"I got game, but I can't get anywhere with these chicks. They're all frat-boy cock-sockets!"
by tippy24 October 14, 2007
Get the frat-boy cock-socket mug.
Below average in size.

Slightly pencilly.
Brennan: "How big is your dick?"
Dean: "I have a frat cock. I'm a grower, not a shower."
by sororitygurlz March 9, 2017
Get the frat cock mug.