hahaha. awww. chins are so crazy......
i honestly dunno lol......from what I have seen both on these forums and on the internet since I got my chin over a year ago that seems to be just a natural part of owning a male chin, but I've never looked too deeply into it since it doesn't really affect me, but I'm sure someone else on here is more knowledgable than me WRT this so hang tight!
I don't know if they "NEED" to do it but I know that chins can be trained, but it does take quite a while. So every time he tries you could just gently push him off or move your hand away etc. and have a command such as "NO!" until he gets the picture