I forget the name, but there was a potion of Love that turned you homicidel if the target of your affection did not return said affection. Or if you thought someone else was after them, they would become a rival to be evicerated.
I think the Dragon/Succubus would work better, but still nasty either way. Imagine an acidic kiss AND a level drain.
As an aside, make sure she is only wearing clothing that would be a move equivelant action to doff.
Paladin #1 " I take a readied action if she casts a spell."
DM "Well, she isn't casting, but she is fiddling with her zipper."
Paladin #1 "???"