Snuff

[Arria]

But that didn't quite fit, and I realised that it wasn't what this is about because none of us seriously imagined that I would kill them; the thrill was just that I could, that I had that power and wasn't afraid to use it.

That describes the thrill I feel during breathplay very well.
If I didn´t trust my play partner to stop before it got really dangerous, I would not consider breathplay with him...

As I said elsewhere, I don´t know how far I would go if I had no family; but with things being as they are, realizing a snuff fantasy is just out of the question.