We engage in anal sex, and I have never used an enema. (I am curious as to why you felt the need to specify that you weren't going to do it yourself actually.... did you think we were all going to judge you?)

In the spirit of education, "fecal matter" doesn't actually move down into your lower bowels until it is ready to be expelled. If you feel like you have to go, go. And if you don't feel it, then things should be fine.

If you have a healthy diet and are fairly "regular" in that area, things should be pretty clean. You body does a pretty good job of cleaning itself, when given the opportunity.

Of course things get messy from time to time, but that is honestly just the risk you have to run when engaging in this activity. I doubt that even enemas would protect against this in 100% of cases, but someone who actually does that will have to comment on it for sure. When it does happen to us, we just stop in the bathroom to get washed, and then get back to business. But probably 95% of the time, everything is fine.

As for safety, once something is in your ass (be it a penis, toy, fingers, ginger, etc.) it needs to be washed before it goes anywhere else. Some people get around this by using condoms (one for anal, one for other play), which works too.

Use lots of lube. Put on twice as much as you think you need, and then use more.

Go slowly. Very few people start their anal sex adventures with actual intercourse. Start with fingers or small toys, and work your way up.

Use your body as your guide. It will often hurt at first, but it should be a pleasant, stretchy hurt, not a "you are ripping apart my insides" kind of hurt. If it feels like this, STOP!!

And finally a word of warning regarding toys. Anything you put in your ass should have a wide base to avoid it slipping all the way in. The anal sphincter can actually pull objects in deeper, especially during orgasm. And unlike a vagina that is maybe 6 inches long and has a convenient stopper at the end, you are messing around with SIX FEET of bowels here. I have heard horror stories of slim vibes sliding all the way in and out of reach, and then overheating causing internal burns. Just not a conversation you want to be having with an emergency room doctor.