Lay on a pen while masterbating?

Ever since I was a young kid, I always felt the need to place pressure on my navel while masterbating, it makes the orgasim so much more intense for me. I used to lay under the dinning room table and put the leg of a chair on my navel and then masterbate. Now, as an adult, I use a pen. I put the pointy side against the bed and place the other end in my navel, then I lay down on the bed, putting all of my weight on top of the pen. It is such an intense orgasim, I barley have to touch myself.

I always wanted to know if I am the only person who has ever done anything like this?

Is this normal?