Anyone who wants to get into anything even remotely BDSM-y should have mandatory reading of Sunstone first.

There’s a character there who lost her hands because she wanted to impress her dom boyfriend and tied herself to the bed with self-tightening knots. The boyfriend - not aware of the fact - was home late. By that time she lost strength in her arms, the knots tightened and cut off blood-flow and her hands had to be amputated.

This shit is sexy and hot, but dangerous if performed by unaware/inexperienced people.