Originally Posted by MSD

For restraints, the cheap thing to do is go down to the local army/nave store and get a roll of 550 paracord for $5, tie the ends to carabiners, and run them diagonally under the mattress. Get some wrist straps, and clip them to the carabiners. when you'ore done, the rope and carabiners are unobtrusive, plus you can toss them in the garage before you have company over and they look completely innocent.