I made a bondage chair for self bondage once with some bits of wood I had knocking around. One solid rear pole from the ground up and then leg supports for under the thighs that spread my legs wide and a gap between them where they met the rear pole so my ass was left exposed.
I put foot rests on it so when I wore heels my feet were held in position instead of being free - I want to know I'm wearing heels.
Then I finished it off with a sturdy base so I could struggle with no worries about it toppling over.
The straps were held in place and the ankles, below the knee, above the knee, waist, chest, chin and forehead.
For my wrists I attached a series of eye bolts and made recesses for padlocks. I used locking wrist cuffs on my wrists and separately secured the chains through the padlocks and eye bolts. On the end of the chains was a snap link that I could push the D ring of the cuffs into but once in I couldn't reach to release the cuffs. My release mechanism was ice release for the padlock keys. Once the ice melted I could pull the keys to my hands using an attached chord and unlock the padlocks, allowing the chains to be freed and releasing my hands.
I set this chair up with a stand in front of me holding an hitachi wand with a cock sheath attachment. I secured myself after inserting my cock into the sheath and added tape to make sure it held in place. I was usually dressed head to toe in rubber with high heels or ballet boots on and a vibrating and inflatable butt plug inside me. I secured my ankles first and worked my way upwards, securing my forehead last before finally switching on the vibrator and then securing my wrists.
The vibrator was intended to be on timer to keep me in the edge with a few minutes on and a few minutes off. However the first time i did this I didn't set the timer properly and it ended up with me being restrained for three hours with non stop vibrations on my cock. The first orgasm was incredible but then when I realised the timer wasn't set properly things began to get really interesting! I can safely say that I tested the strength of that chair to its limit and I didn't win!