As someone wisely said above, it's not true anal if it's not a bit dirty!! >:D >:D
I usually just wash, and that's mainly for rimming (although myself I don't mind a dirtier asshole, I have to admit >:D)
As for fucking, you don't really need to douche if you don't want to, just take a dump before you have sex so you are empty (mostly cause a full bowel can feel uncomfortable during anal penetration), and wash properly (maybe let the water go inside with the shower head for a more thorough cleaning). And last but not least, if you or your partner are feeling uncomfy with the idea of a brown dick, just USE A CONDOM! This will keep the nasty stuff off the penis and you can safely give it a lick in the end 😉 😉
Douching: if you choose to douche, use lukewarm water. Hot water might burn the area easily (remember, it's far more sensitive than your skin), and cold water can cause cramps. Do not add body wash or soap in the water you use to douche, it can irritate the area badly. Also, do not douche all the time. Douching is a forceful substitute of the "natural way", and doing it very often might make your bowel lazy (aka you won't be able to go to the toilet properly since your bowel and your brain are used to the douching instead).
Antibacterial soap: DO NOT! I repeat, DO NOT USE ANTIBACTERIAL SOAP ON YOUR ASSHOLE, ESPECIALLY ON THE INSIDE! Your bowel is full of bacteria, which however are not harmful to you at all. In fact, they are very VERY important and necessary for your bodily functions. Antibacterial soap kills all bacteria, including this microflora and microfauna of the bowels. If you kill those bacteria, you might get serious irritation, bowel problems, or even an infection (since many of those are helping with keeping the dangerous bacteria away).
Last but not least, when it comes to the bacteria, remember: the bacteria you have in your bowel are natural! Chances are that your partner already has them too. However, in order to make sure that nothing bad happens, THE TOP SHOULD WASH PROPERLY AFTER SEX. And that includes washing the genitals after anal, as well as cleaning the mouth with mouthwash (for rimjobs).
Hope I helped! 😄 😄