A shortened version of "brokeback activity" as to flow better across the lips and articulates of the mouth. Most commonly used to describe a "homosexual" or otherwise "gay" activity.
Chris: *Cuddles up to Blaine*
Sean: I didn't know you dabbled in brokeback activities?
Blaine: Sean its brokebactivities. Brokebactivity. Get with the program, I thought you were up with the times?
Sean: Oh yes, I forgot.