No. Because I talk in a different mannerism. I'll is for something I am sure to do. I is a possibility when speaking of doing something, or talking about how you'll do something.
"I fill your mouth with water," Stating that I, fill the mouth with water. I'll fill your mouth with water states I'm going to do it to him anyway, which, I am not, so no typo.
Actually, may would be used to indicate possibility, and will indicates intention.
So, I may fill your mouth with water would have been more correct.