When your whole world revolves around you and your boyfriend/girlfriend. And It’s only them, no one else. You spend ALL your time with them, and you ONLY hang out with them, and you ONLY talk about them, and everything you do is about THEM. Most likely you will end up having: no friends and no personal space or private time.
Friend: "Hey, wanna hang out today?"
Hyberdater: "No, im seeing ____ today"
Friend "Oh ok, how about this weekend?"
Hyberdater: "Well...I'll be with ____ then too"
Friend: "Uhm..alright, so you comin' to my birthday?"
Hyberdater: "Oh darn, I have plans that night with ____"
Friend: "You know what..forget it. Have fun with your hyberdating"
We know squirrels hibernate, and they dig in the dirt to hide their nuts... So... The Hibernating Squirrel is when you are doing a chick doggy style in the ass(Digging in the Dirt) and you tuck your balls inside her vagina (Hide your nuts)