funny?

I know Chad and I shouldnt think things like this are funny anymore but over the weekend Austin asked Chad and I a question so sincerely but it was gross and funny so we both laughed he got a little upset, but you'll see why, this is how it went:

Austin:"mommy?"
Me:"yes?"
Austin:"If you stick your hand up your bum really far, will it come out your mouth?"
(laughter from the front seat from Chad and I)
Austin: "stop it!"
Chad: "ya buddy, it would, but dont ever try it, your smart to be able to figure that out."
Austin: "I know"