i spend a lot of time cleaning out before bottoming. i have a hose that attaches to the spout in the shower with an attachment you stick in your ass. i keep it in until i cant hold any more water and then evacuate. i do this until im clean. it makes bottoming much easier since you can relax and enjoy getting fucked instead of worrying that you will give your top a chili dog
For pete's sake YES...if you're going to bottom, PLEASE clean yourself out. No one likes (ok, I'm sure some do...no judgment) the smell of poo or the sight of it when you're enjoying yourself down there.
Granted, accidents can happen even after cleaning yourself out..but you can then say that you tried =)