The act of cock blocking some one for their own good. When some one is over looking the fact the chick they are trying to score with is a major whore and will end up giving them something.
Nick: You owe me i totally
Aids Blocked you last night.
Kyle: I know i was to drunk to think, if only you showed up up an hour earlier i think that red head had something.
Nick: The only red head there was my fiancee.
Kyle: My bad.