Because merfolk are a sterile hybrid (that is, they cannot reproduce), the continued existence of merfolk culture is contingent on the ongoing flushing of semen. Please give generously.
Person 2: I'm gonna hit the shower, make some mermaids, and do some homework.
Person 1: You know, shower jizz doesn't technically fit the definition given above.
Person 2: Well at least it's clean of shit.