Lifestyle tips

Expanding

I'd like to know what methods I can use to expand/blow up my stomach/belly really big using air/liquid/solid in a way that would not result in permanent weight gain, something that would dissipate in a few days or so and put me back at my usual size.
I've considered drinking large amounts of sugar-free Jello pudding (non-cooking kind) mixed with almond milk or 1% milk until I bloated up.
What about just plain water, if I add a bit of salt to help with electrolyte loss? How much salt per quart of water?
Any foods that will do it (bloat me up on a temporary basis, and then digest and excrete) without putting on me any extra weight? Lots of grits or oatmeeal?
Any helpful advice or personal experience in this vein?
Thanks for any help
Porsche guy
2 years