I have been trying to search on this and am not coming up with useful stuff, so I’m hoping the vast hive mind of the internet can help out.
In my story, “The Bride Replete,” I have an alien race which uses some of the members as repletes to store large quantities of food in their crops (a sort of sac for, well, food-storage). I had thought of using sodium bicarbonate and water to create a constant pressure in a replete’s crop during the process of stretching them. Would this work? They do have a sphincter they can close and open voluntarily. Is there something better?
Edited to add: This is a totally alien planet with no human interactions, so brand name things are right out. The technology is roughly equivalent to mid-1800s England, though there’s room to play, since it’s another planet.
Edited further to add: This is an artificial process to speed up the way it would work naturally. It’s someone using science to do what would naturally happen by just eating more food everyday. This is a way to prep a new replete for when the harvest season begins.