anal???

So boyfriend really wants to do anal and I'd really like to try it too. I've read all the stuff about how to warm up to it, but honestly, im not scared of the pain im more scared that i shit everywhere?? I know it comes with the territory but I'd rather avoid it all together. Any tips on making sure im clean up there (please i really need in detail descriptions how to get clean) and has anyone actually had a bad experience with this?