Besides douching properly before a session as mentioned above, the only other thing I recommend is a healthier diet. Stay away from red meats and fast food especially the day you plan to have play time.
A quick trick that works for many is taking psyllium husk (Metamucil). Its available everywhere and is not a suspicious purchase as it is commonly used for constipation. What this stuff does is neatly wrap up your stool so it comes out solid and clean, leaving little mess inside. It makes cleaning a breeze.
Additionally, if you don't want to purchase a dedicated anal douche, you can buy a syringe from your local drug store. These are commonly used to administer medicine orally (and in cooking too, I suppose) but can be used to rinse out your butt with warm water, just make sure you buy one with rounded edges and to apply lube before inserting. Rinse until only clear water comes out and you're set for a clean session.