Let's all get together right now and stop acting like mermaids are hot. The bottom half of her body is a fish! Ick and yuck and ew! If I'm taking off a chick's pants, I'd rather find a penis than a halibut.
For that matter, I'm not even sure fish have vaginas, so you probably can't have sex with a mermaid anyway. And while you're making out with her, she'd probably just release a couple million eggs all over your bed without warning.
Now you may be saying to yourself, "Yeah, but what about oral?"
Let me remind you she can't walk. Do you want to be the guy dragging a fish woman up the the ADA ramp at your apartment just so she can fellate you?
You may continue, "No, no, no... She blows you off the back of the boat. Obviously. Take her home? Jesus, you gonna make her breakfast too?"
Of course I'm going to make her breakfast. She just gave me several pounds of caviar absolutely free, the least I can do is fry her up an omelette.
You continue the argument because you're disgusting, "Fine, Falcone. Let's just switch it. She's got a human bottom half."
That's the worst idea! Sure you can have sex with her, but the whole time you're staring into the cold, unwavering eyes of a giant fish head as it slowly suffocates because it can't breath out of the water.
Let's all decide here and now to stop turning fishwomen into sex symbols, at least until Ursula gives her legs AND her voice back.