I guess we can rule out super glue, duct tape, and nail guns. 😉 You can do your own under the mattress restraints using lengths of rope or several leather belts. . Buying the padded cuffs to then attach is a good idea. A sleeping bag will allow some basic mummification. The hog-tie, or in your case hottie-tie, suggestions are good too. Y'all have fun!! You may be able to buy a bed frame at Goodwill or a furniture rental store or on Craigslist for cheap.