In addition to being a situation in which two people date so exclusively that you rarely see them, the hiberdating couple will make occasional public appearances. During these appearances, the two will never acknowledge anyone but each other, never stop touching/caressing each other, and will annoy the living piss out of anyone and everyone in their vicinity, especially used-to-be friends of the hiberdaters.
Wanna go hang out with Kenny and Marissa?" "Sure, if you want to puke your guts out listening to them talk goo-goo to each other... they've reached hiberdating status ever since Kenny refused to take his hand off Marissa's knee during Science class
"I Thought Those Two Were Together?" "They Were But They Were Just Hiberdating.They Do This Every Year. First Nice Weekend Out They Called It Quits. Come October They'll Be Back Together."
When someone ignores their friends in favour of the girl/boyfriend they are dating at the moment. When they are unable to be in the same space, touching each other, they cannot be parted from their phone, where they are undoubtedly messaging them. They will mostly ignore their friends, unless they feel the need to insult them or defend their relationship. To sum it up, it's when couples spend over 60 hours a week in a vc.
Person 1: "Man, I haven't seen 3 for ages."
Person 2: "Yeah, not since they started dating 4."
Person 1: "But 4 lives overseas, how does that work?"
Person 2: "Over 60 hours in a vc, that's how. I wish they weren't hiberdating, I need their help with this job."