>>56905
Think of hypnosis kind of like meditating, they use the same principles. You have to will yourself into it but it can manifest in seriously physical ways because your brain has control over a lot of unconscious processes that you don't normally have access to. So hypnosis really can make you experience - just for example more or less pain because your brain controls your feelings over those things.
"Feeling babylike" is also something constructed, it's in your head. How much control you have over your muscles, including sphincter and bladder - that's all as much mental as it is physical. If you convince your brain to let go, it will. Hypnosis is about accessing those parts of subconscious control.
TV shows like to depict hypnosis as though it's something you can do to someone unwilling, but it really requires active participation and intent from the target.