When a girl touches my belly, it is very sensitive, how do I overcome this?

So when a girl just touches my belly, it gets really sensitive, and it makes me laugh really bad, that it starts to hurt, I know that when I touch it myself my subconsiousness knows that I touch it and not somebody else, and in that case nothing happens.

I really want her to be able to touch my belly when she wants to withouth me having any problems with it.

My question to you is: “how can i make it dissapear”.
All suggestions will help me, also, if you know more about the whole subject of “laughing while being touched by someone else” is welcome to, since I find it interesting how the body works.

Thanks in advance