A hookup that actually has real emotion behind it. Not a drunk hookup or a random hookup with someone you've gone on a few dates with that you feel lukewarm about. A hookup with someone you really like. You can usually tell if it's an emotional hook if you don't want them to leave after hooking up.
Ryan: "So, how was it last night?"
Cal: "Dude it was actually great. The hook is so much better when you actually like them."
Ryan: "The fabled emotional hook?"
Cal: "Truly. Didn't want to them leave right after"