1. noun: Any act of cuddling beyond normal, chill holding hands. This can include full-contact cuddling, kissing, making out, or sex. It is often used to deter nosy friends, (see example 1.) when they want to know more about your relationship than they should.
2. noun: A rare case is actually when a couple is holding hands--and nothing else--but has manage to warp it into something incredibly sexual. Interesting to watch. This form of extreme hand-holding should perhaps be it's own fetish.
"Hey! What did you and _____ do last night??" -Nosy Friend
"Nothing much, a little extreme hand-holding." -Friend in Relationship
(Conversation ends, nosy friend thwarted)
DuDe!!1! Look at those two! I had no idea you could get THAT into holding hands.... extreme hand-holding ftw.