I'm currently working on a story about a man and two women indulging in a weekend of self bondage with the three of them bound hand, foot, and neck to a bed under a mirrored canopy.
One of the twists is the keys to their restraints dangling over their bound hands by a string anchored in solid blocks of ice.
Complication number one: The thick red satin comforter over them that provides a barrier between their hands and the keys. Secured in place, they can't remove it until a timer releases the locking mechanism.
Complication number two: They each take a sedative before being restrained that forces them into a deep sleep before the time