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
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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 08, 2017
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