I've used shower and bathtub enemas for years. I unscrew the shower head and make sure the end of the hose is smooth, if not, I take a little electrical tape and wrap it tightly around the end. For bathtub enemas I have an extra length of hose I screw onto the shower hose, then I can lie down in the tub with my legs up in the air. When a kid, I used to be able to straddle the old claw type bathtub. I was a sex maniac when a kid and home alone. Oh, if my parents ever knew the sex scenes I had by myself when they were out for the day. Ha, I used to get hard before they even left thinking about what I was going to do when they left. I always waited a bit in case they forgot something and they came back.
That happened once, I was partway into a nice large enema at about 12, and I heard the front door to the house open, my mother had forgotten her purse or something. I did not get caught, but it was a good warning to always make sure I had given them enough time to be out of town. The old bathtub when growing up had one of those combination mixing faucets, and then one could slide on a rubber shower hose that went over the bathtub spout. I got the mix and flow right and then pulled off the shower head at the end of the red hose, then I spread my legs over the edge of the old claw foot tub, put a little ivory soap on the end of the red hose and up it went up my asshole.
I took many, many many, enemas that way as a kid. It was ultra fun! I started cuming at about 10, so I had some good years back in my parent's house. I never had any really close friends that I knew of that also did that, ha, maybe they did, just don't know, the situation just never arose to have a playmate, I sure would have welcomed one. I started with enemas at about 5 or 6 and in high school I was up to about 3 or 4 qts.
Back to the shower enema, I adjust the flow way down, the right mix, and regulate the pressure by squeezing my ass cheeks. I let the whole thing go in the shower, I find that very hot and it's an easy cleanup. Some find that gross, but it's just what I like. Sometimes I use a mirror so I can see the whole hot show!
If I'm limited for time, then I take a washcloth and press it over my asshole and waddle along over to the toilet. My new house has a nice setup, deep shower and almost a medical looking toilet right next to the shower. It's a real turn on, Just be sure the tap water is safe in your area. Also, if jerking off, watch the pressure that in all of the excitement you don't let it build up too high, generally the water just blasts by the hose up my asshole. I had some very very very very very very hot times as a teenager doing this and still do. Huge hardon and all. I also use binder clips (the large ones) on my tits, I like tit action, so the enema, plus my tit action and a slow jerk off is oh so hot! I'm horny now just thinking about it all.
Be careful of too many plain water enemas over and over again at the same time, some real experts in this forum have talked about that and electrolyte balance, etc. I can't do repeated enemas, I get so excited on the first one I just have to cum and then lose interest in another, although, sometimes, in a couple of hours I'll do another because thinking about the last one gives me a huge hardon!