Ok I respect denuseri but got to disagree. Also, "for all intensive purposes"? (shudder) I am not the grammar police but it is: "For all intents and purposes."
Now, I agree if the dom does not allow a submissive to masturbate, ever, out side of a scene then ok they are morons.
But, if my sub masturbates without asking for my permission to play with my toy, then she is gonna be in trouble.
Control does not always mean denial but you have to deny access sometimes or the request for permission loses its meaning.