In the popular game Call of Duty: Modern Warfare 2, "bb" will result in crouching then standing up. When done over a dead body or someone that is alive but doesn't notice you this is called teabagging
. "bbbb" will result in two teabags and is usually done to show superiority and dominance or just to be a funny fag douchebag.
See also: showboat
Guy 1: Dude that guy is planting the bomb and he doesn't even see you. Take advantage of this monumental and rare occasion!
Guy 2: bbbb done.