I want to say (as someone into a lot of "things") that our freedom ends were the otrer's start, but theres no way to know that point, cause we dont fully know anyone, not even ourselves.
How can you fulfill someone's wishes of being raped, if that person doesnt know about that? i love being hit, that's one of the main reasons im a great handall goalkeeper, i love the pain cause it gives me a sensation of strength, stress release... but i dont like being degradated by it like a slap... I know that cause i experience it.
The point is not how far do we go, is how far can we get.

(And about freenight, he is to blame for his likes, but that its not a bad thing, i think i share most of them)
pd: a Sadist is someone how feels pleasure when inflicting pain, domination or degradation on others