I agree with everyone, I- bolts are the way to go. We have 1 at each corner of the bed. For convenience we have ankle and wrist cuffs with heavy duty carabiner clips to attach to the I-bolts… Either directly or indirectly, with a chain or rope. Chains are louder but with a clip at each end there’s no knots required and you could clip at any link in the chain for adjustable length. We also use multiple pairs of handcuffs to tether me to the bar(s) on the headboard and/or footboard.
Hope that helps. The Internet is always a source of infinite inspiration. Save a bunch of pics with elements you like, and make the end result a unique design incorporating all the features you want, and none of the features you don’t. That’s what we did. 🙂 good luck and have fun!