LDSU stands for Long Dick State University. Real heterosexual men with game — that act like real men, graduated from this made-up school. It separates the men from the boys, the ones with real game and swagger.
Mel: Yo, dude called to ask if I slept with his girl last night.
Ron: WTF! Are you serious? He didn't go to LDSU did he?
Mel: Nope. Because if he did go to LDSU, he wouldn't be to overly concerned about that broad anyway.