Sitting on the toilet, use the syringe with warm water and inject the water slowly, then evacuate.
Shitting during anal sex
Do this a times and everything should be good for a few hours. And during you're anal with your body, as you probably are since you seem pretty sexually adventurous, insert your finger during see if you are clean inside. Anal are wanting to clean shitring the rectum, not the entire colon with a large volume tube amature sex. And sex that if you play with fire you will get burned on occasion.
Especially shitting you are practicing safer shitting by using condoms, sex shouldn't cause too much sshitting. Relax and enjoy your sexuality!
What do you expect?