Many people describe being in a hypnotic trance as similar to being drunk, but without the negatives! It’s not uncommon to be very playful (because disinhibited), and generally people respond to suggestion in an uncritical, almost “automatic”, manner. You can not, however, be made to do or say anything you don’t want to – you’re not “under control” – and if anything really objectionable or harmful to you was to be suggested, you would not respond, or – very likely – come out of hypnosis immediately.
A minority of people (under 10%) have the combination of personality traits, attributes, and motivation to enter very profound trance (a “somnambulistic” state) during which they can open their eyes, walk around, perform complex tasks etc whilst remaining deeply hypnotised. Such individuals may experience trance amnesia, remembering little or nothing of what happened whilst in hypnosis, but even such individuals can not generally be forced to do anything against their will. They simply have an unusually high capability to concentrate intensely on instructions, ideas, focal points etc, and to suspend critical judgement in order to enter an “alternate reality” in which their imaginative capabilities are given full reign.
In short, hypnosis is really nothing more than an intense form of interpersonal communication where one person guides another into a state of mind in which attention is completely absorbed in whatever is being suggested. Most “normal” people enter spontaneous trance states regularly (eg “daydreaming”; performing repetitive tasks on “autopilot” whilst thinking of other things; being “lost” in a book, movie, piece of music etc), and hypnotising someone is simply deliberately inducing such a state for some specific purpose – psychotherapy, entertainment, relaxation etc..