Green’s Dictionary of Slang

(US gang) the rolling of a dice by a female recruit to a gang to ascertain how many members will have sex with her.

1997

G. Sikes 8 Ball Chicks (1998) 101: Rumors spread of a practice among some gangs called ‘roll-ins.’ A new female recruit rolled a pair of dice and whatever number appeared determined how many guys would have sex with her.