If you want to shrink and become Katelyn's slave then all you have to do is eat the medicine she gives you, which is her chewed up food. With eating her food your body will absorb her saliva which will make you shrink. At first the shrinking process will go along slowly but the smaller you get the more potent the medicine will be to your system and the faster you will shrink. After she finishes chewing up exactly enough for you, and spitting it into a baggie, she run off to ship it to you so you can begin the process.