When a chick cockblocks your bro from hanging out with you. Both guys must be heterosexual so it's not an actual "cockblock," unless both are homosexual, in which it is.
You: "Dude, lets go play frisbee!"
Bro: "Yeah, bro!
Chick: "Aw, baby come stay with me!"
Bro: "Alright, see ya later, dude."
You: "Aw, man, I just totally got bro-blocked!"