Like Ra's Naughty Playground

Frozen string

1. Measure the distance between the anchor point (a hook in the ceiling? a lamp?) and the place where your bound hands will be.
2. Add ~15cm for the knots on both ends plus extra 15-20 cm (just in case)
3. Neatly coil the string in a bowl of water leaving both ends outside of the water.
4. Freeze the water.