Well, this is all conjecture of course but here goes:
For me mutilation starts when you are really altering and damaging the body in a way it can't go back naturally to what if was.. like if you whip a girl's back very hard, the skin will be cut, will heal eventually but with scars that won't ever go away unless surgery.. maybe this seems light, of course but it is altering her body. But you can do that at will, with very limited risk of killing her.
Removing parts of the body, like toes, fingers, foot, arms, breast, all possible to do it without killing her, but its tricky, blood loss is a major issue when you work at this level, then if you want to be "realistic" in your fantasy, then you have to worry about infection, because doing any of that in a "dungeon" room, will kill her fast...
My view on that is enjoy your fantasy, it is just that, so don't add elements that will ruin it for you :)
Having that said, when fantasizing about abusing and torturing a girl, i know for sure mutilation will come to the mix, i like to think about it more in late stages and with no complications.. you wanna strip her legs to the bone, lets just say you can if you are into that...
Your fantasy, your rules!
I like to really take it slow, like when you actually remove a part of the body, she has sufered so much already that is really just a "killing blow" for that part, just to take it out of the fantasy and focus on something else...
snufing is not the turn on in my case, its the slowly and very painfully getting there ;)
