Nope, not even close. Nope, nope, nope nope nope. Mermaids (and whatever male mermaids are called) don't do nuffin like that nasty icky sex stuff. They don't even have those body parts, in fact.
No, mermaids reproduce in the classic and proper way. They get married, engage in a bit of innocent closed-mouth kissing just a little, and then the storkfish brings their babies right to their underwater door in the night.