Chumpuckle

Someone who you are friends with, but you hit them in a caring way. These hits, however hard, do not and will not ever affect your relationship.

Person 1: "Do you actually like him?"
Person 2: "Yeah, how come?"
Person 1: "Well you're always hitting him and stuff, are you sure he's okay with it?"
Person 2: "Yeah, of course... we are chumpuckles!"