Whenever you're girlfriend/boyfriend tells you to do something, you will do it in a heartbeat because you know it will please them.
Whipped kid: "Aw dude, that sucks. Me and my girlfriend never fight. She always comes over to my house and we watch movies and sometimes I even cook for her. She's amazing. I love how we never argue. Maybe sometimes but not alw-"
Friend: "Dude! I asked you for advice! I don't give a fuck what you and your girlfriend does."
Whipped Kid: "Well I'm just trying to help. I mean, our relationship is so different from everyone else's. She's so sweet and nice and she always listens to what I have to s-"
Friend: "DUDE! You're fuckin' whipped man!"
Evolved human: did you hear that? it sounded like a pre-humanoid predecessor, giving off a mating call for antelope..!
2. To be utterly controlled or dominated by one's partner, as in girlfriend, boyfriend, or spouse.
Xander: What happened? Is this another tale of whipping?
Felipe: Yes! John was getting whipped by his girlfriend AGAIN. She told him to bring home a tree that she found on the ground from Wilmington to Atlanta, so he picked up the tree, put it in his lap, and held it there for four hours, and then dropped it in the middle of his driveway.
Xander: Yep. That's John for ya.