One time, when I was at work (this was a job that I had years and years ago) and we had lots of time, we had this chess board and played alot.
Anyway, this guy and me were playing chess and this other kid sat at a side between us (at a four-sided even square table). We were playing and playing, etc. then suddenly he put both of his hands below the table and started rocking back and forth sort of up and starting making these sounds like "MMMMMM.....oh yeah" and "oooohhhh ughhh". Well, we started getting a little freaked out and told him...."hey buddy, there is a time and place for things like that and now it is not" or "maybe you need to go to the bathroom?" Then he sat up and was like "What? What? I wasn't doing anything"
Needless to say we quit playing chess when he was working.