Yep, even though it isn't necessarily considered a sanitary part of the body, the flora and fauna are in balance... so introducing any foreign bugs/germs/ etc. can be problematic.

More importantly, pesticide residue can be present. What you can tolerate orally may be deadly anally.

So WASH everything you intend to introduce into that lovely bottom.

That being said, search this forum for the term "figging." It's about ginger root and anal play.