boy1: bro, what happened last night?  boy2: i don't know?  girl1: i'll give you boys a hint, you two played bumperballs on me all last night
when two men are having intercourse with the same woman, one man is in the vagina, and the other in the anus
"boy1: bro, what happened last night?  boy2: i don't know?  girl1: i'll give you boys a hint, you two played bumperballs on me all last night" What is the definition of "bumperballs"?