BBB's Gambit supposes that when you claim scum and ask the town to lynch you, they will assume you are Jester, and proceed to not lynch you.
When to Use
The risk, of course, is that the town will either take the claim at face value, or realize the gambit and lynch the player anyway.
The codifying example was executed by buhbuhbam13, who, despite not intending to win the game, ended up successfully surviving and winning as scum. Here is a small excerpt from that game:
[21:24] I be Pulak: I AM TOLD THAT TEH SCUBASTEVE IS TEH SCUMZ [21:24] I be Pulak: WHY IS BBB NOT DEAD (Time Passes) [21:30] buhbuhbam13: I AM SCUBASTEVE I AM SCUM AND KILROY MADE AN INCREDIBLY OVERPOWERED TOWN SETUP, LYNCH ME SO I CAN LOSE ALREADY PLEASE [21:30] OmanOC: jester [21:30] I be Pulak: NO [21:31] OmanOC: BBB looks like jester
At the time, most Jesters did not immediately end the game upon being lynched. As the role evolved to be able to win with other factions, this gambit lost much of its utility.