I haven't seen any of my fellow bottoms mention this yet...but you need fiber in your diet! If you're super anal (hah!) about being totally clean down there, then you should take a daily fiber supplement like metamucil or the cheaper store brands. It makes everything in your digestive tract bind together into big logs and makes cleaning up much much easier (and faster)! Also, just eat healthier! If you eat a bunch of fast food and junk snacks, well you're gonna have a mess to deal with.
I've seen some people mention taking 30 minutes or an hour to get their butts ready for pounding...that's ridiculous and kinda OCD. Unless you're dealing with long cocks/dildos that penetrate past your rectum into your sigmoid colon, a quick water douche is all you need. I've never used enemas. Just squirt some water up there, let it out, repeat, walk around for a minute or two to let the remaining water move around and push out the last few drops. Good to go.