How do you remove something from the anal cavity?

If the "something" is already in the anal cavity, the Emergency room at the nearest hospital is probably indicated.

However, if you were smart enough not to put something in first and worry about it afterwards, then the answer is "Have a great big handle on the something so that it will be possible to pull it back out" Look at the design of butt plugs---- they are made so that you can't lose the thing inside the anal cavity.

Good Luck!