1. To masturbate. Deriving from the fact the sperm grow into children, and by the act of "beating off" one releases these.
2. To masturbate. When referring to ones balls as "the kids", so as to infer that in the process of masturbation, ones balls will come into contact with ones hands at the end of the sliding motion
No one at the club wanted to hook up, so I went home to beat the kids.