The act of screwing (literally and/or figuratively) another in an intentionallydominating fashion so as to derive pleasure from the message being sent.
Why is our dog humpfucking the shit out of all the other dogs in the playpen? We'll get kicked out for sure!
When your brain can't decide whether you want to hug / snuggle / fuck - so you attempt all of them at the same time. Usually caused by a combination of loved-up affection and raw lust