For me it used to be Vaporeon (male), then Gardevoir, then Lilligant, then Sylveon, but now I'm thinking Chandelure. Its base design can only go so far, you have to think about what it can do. Chandelure is a Pokemon that eats life essence.
It's also a lamp. Lamps aren't sexy. But, it's a ghost lamp. Ghosts can do crazy things with hallucination and visions and false feeling.
Once you stare into its flame and give it energy enough to do so, I see no reason why a Chandelure wouldn't get possessive and happy around you, and make you hallucinate and feel her body in a way that it may or may not be such as pic related. Even if it killed you by fucking you to death, it would keep your soul. That's some sexy shit.
well if you're into submissive pokemon i guess audino is pretty good