Ok why is it when u have a orgasm your leg move and u wanna scream?
That tiny bundle of nerves between your legs is still nerves so after having an orgams which is pure pleasured bliss, your muscles spasm and you want to scream because either it hurt you or it felt good, it's you're body's instant reaction to what's happening to it.
That's just part of a gooood orgasm.
You are lucky, some girls don't have it that good.