When more than one member of a family (Brothers for example)
Ejaculate In the same woman or place at the same time.
This would happen while running a "Train" Or any other group sex acts that involve more than one male
1. "Those two guys gave Robin's face and tit's a family paintbucket.
It was quite a thing to see."
2.They let off a family paintbucket In That Cup and made that girl drink it