Placenta slap Share definition Flag The act of slapping ones baby daddy with placenta. Kaya just had her baby and the father isnt around so she's decided to remind him he's a douche by placenta slapping him. Placenta slap by Mumblina24 July 12, 2015 0 0 Get merch Get the Placenta slap mug. Buy Now — $32.95 See more merch