If the trick comes over to talk to you, you may certainly make introductions. You need not be specific about how you met this person, and in some settings, it would not be appropriate to do so. But by all means, avoid telling them in front of a third party that you don't want to see them again. Briefly, an enema is designed to empty and clean the lowest part of the bowels. Water is allowed to run into the rectum, and then expelled, carrying with it whatever was in the rectum at the time.
Enemas are a good thing to do before engaging in an evening of anal sex.
You clean the tissues so there are no gritty remains left to scratch the delicate rectal walls. Some folks are left with unpleasant associations, while other luckier ones saw the erotic appeal right away. For more information read Anal Pleasure and Health by Jack Morin. If you're new to this site, we strongly recommend that you visit our home page to get a better sense of all that we have to offer.