To masturbate in one's bed, followed by going to sleep without getting up in between. Can be used as either a verb or a noun.

This move is very similar to the Slop and Drop, but must be done with a partner. To perform the Slap and Nap, a man has sexual intercourse with a woman. Upon orgasm, the man collapses on top of the woman and falls asleep, thus enhancing both the sexual act and the ensuing nap.

Slap and nap is the act of masturbating and then using that relaxation to go right into a nap.