My country is an example where it failed anyway. Whether we are considered to have tried regulating it or not is a bit complicated.
> to agree to being eaten by a friendly cannibal
They had standards though, you'd have to work to gain the respect for anyone to want to eat you as a mortuary ritual.
1. the right to not have someone else do stuff to your body
2. your right to do anything to it
Number 1 is pretty well established.
Number 2 less so, and I think that comes down to us as a society noticing that many people can't be trusted with full access here. Ask any clean addict and they will tell you what a colossal mistake it was to start using the drug in the first place. The regulation of what you can do with your own body is, in my opinion, a regulation to protect future you from present you. Because we all know what the present you has worse impulse control and judgement than future you would like.