The following infographic on ass cleaning courtesy of Hermione the haemorrhoid may be disturbing to some viewers but if you're too squeamish about poop to even read instructions on how to clean your ass, much less actually go about cleaning your own ass, being a bottom maybe isn't for you. That's ok, oral is fun too.
I only ever do the Fast clean up described below. I never receive fisting or anything that huge so there's really no need. I've seen the slightest trace of shit on a condom after bottoming so Fast seems to be working fine.
I do it a little bit differently to Hermione. I have what they call an "enema bulb" in the infographic. I've always called it an Anal Douche rather than an enema bulb since I always thought of an enema as being a deep clean like the "Full" process.
I start by going to the toilet as normal about 45 minutes before I'm going to be receiving a guest. Bathroom fan on. Toilet window open. Wipe and flush. Then I fill the douche at the bathroom sink, put a drop of lube on my finger and lube my asshole and the tip of the douche nozzle, go back to the toilet, insert, squeeze, keep it squeezed while taking it out, wave magic wand, exclaim "Expelidoushius!" push the water out of my ass, wipe, flush and then go refill the douche and repeat a few times until the water comes out clean. This usually only takes a few squirts. If I've douched a few times and it seems like the douche isn't going to be heavy enough artillery in this instance, I switch to the shower hose technique as per Hermione below.
Once the water comes out clean, I refill the douche one more time, insert and squirt, but this time I leave the water in, lube a finger and insert my finger as deep as I can while keeping the water in. Easier than it sounds. The water won't escape. Being full of water makes it easy to check around the upper ring of muscle that I haven't missed anything. If any stray chunks are lurking, they'll just bump of my finger tip, dislodge from where they were stuck and eject after I remove my finger and push the water out.
Then I insert two fingers and thrust them in and out a bit. This seems to help release any water that might have gotten trapped above the upper ring of muscle. If the last bit of water that comes out isn't clean, I douche again until it is. Then I alternate between inserting a finger and drying my finger on toilet paper, insert again etc until my ass is too dry inside to easily re insert.
Then lastly I jump in the shower and wash thoroughly with soap, dry off and clean around the toilet, bathroom sink and shower with antibacterial shower cleaning spray. I clean the douche using antibacterial toy cleaner and hot water, put it away, wash my hands once more and that's it. Ass mischief ready to be managed.
This all probably sounds quite complicated but actually only takes a few minutes. I see a lot of male, bottom clients who are not clean. If I see or smell shit while topping, I usually stop topping at that point and politely direct Mr Dirty Bottom to the shower. Then when he comes back, switch to doing something else other than topping him. I suspect a lot of them don't clean themselves in any way but I also know a few who do attempt to clean themselves but always seem to fail to actually get clean. I suspect the step they are missing is the one I mentioned above with the last douche and then leave water in and finger.