LOL. do you think this is a crazy bet that me and my friend made?

My friend bet me to see who gets a longest tummyache at a movie theatre tomorrow and to cause that, one of us has to order lots of snack, like popcorn, nachos, anything they sell at a theatre. So whoever, went to the toilet first, will have to treat to a waterpark. I am in. But if I get a tummyache, what should I do? How do I hold a tummyache? Oh the rule is no rubbing tummy allowed. -,-