Hi, I would like to start with a passive fisting with my friend (am over 18), so no lectures like harmful fisting is please
Currently, my Anus creates objects of 4cm diameter.
How long does it take to introduce big things to 8cm or 10cm (diameter)?
I would practice every other day with a inflatable buttplug.
This is quite different, everyone can relax as well as well. From that, you do not put a temporal goal, but work slowly and look like it works. If you set yourself under stress, it is more likely to work less fast and come to injury faster.
This is very dependent on the body. In some cases, this is very fast, with others slowly and at the same time at all times.
Just start and then you see if that works. Think there everyone is different.