You get a dog collar that makes five different noises when you press five different buttons on a remote controll.
Then you hypnotize your girlfriend to do something whenever she hears one of those sounds, and is wearing the collar.
Badaboom, badabing, remote controlled girlfriend.
Is your girlfriend too loud? Press the button that makes her forget how to speak.
Does she stay up too late? Not with the nap button.
Heres an example of hypnotis used in a sexy way
[spoiler]Hypnotized a girl to orgasm[/spoiler]
If you don't want to study hypnotizm, but you don't want some hypno doctor to know about what ur doin then you do something called autohypnosis.
You pay a professional to hypnotize her, then you say to her, "Whenever I do this ____ you will instantly be hypnotized."
Be carefull though, because if you do something like, "Whenever I say the word sleep" then you could put her into hypnosis on accident.