Hand friend

When you don't have any real friends, so you draw a face on your hand and move your thumb to make it talk, (or do other things) so you don't feel so lonely.

I got mad head last night from my hand friend.

Second Hand Friend Fist Bump

The fist bump exchanged by two people with a mutual friend.

I don't know the kid but he's also friends with Alex, so we engaged in a Second Hand Friend Fist Bump.