1 definition by L. marx

F.B.I.

F.B.I. stands for floppy ball index. The index ranges from 1-5, 1 being really tight, and 5 being the floppiest it can be.

guy one: Hey dude, whats your F.B.I.?

guy two: (grabs balls and feels around) I'm at about...a 3.

by L. marx January 25, 2006