My wife usually gives me a weekly enema and ends it with a blowjob, which sends me over the moon. Unless she is not in the mood or we don't have enough time that day, my enema is generally preceded with me either going down on her or making her come with my fingers and, time permitting, some good old fashioned PIV sex.
When we were a bit younger, we'd often incorporate the enema earlier in the festivities. She would insert the nozzle - at that time usually a DBC or a baloon-tipped plastisol retention nozzle - and then I would go down on her. To paint the scene, the bag would hang on an IV pole next to the bed, we had two six-foot hoses linked together, and she'd release the clamp and control the flow by pinching off the hose with her fingers. When that was all set up, I would just feast or her incredible pussy. Making her come with my tongue is one of my absolute joys in life. And then after she came I'd take her in the doggy position while I held or took the last of my enema. It was absolute heaven when all went well.
But it wasn't easy. She has always taken a very, very long time to reach orgasm - even when she was younger, 30-45 minutes of stimulation was the norm. She has anxiety, and the impact of that on her brain coupled with the meds she takes to control it makes it difficult for her, so she REALLY has to focus on her pleasure to get there. I don't generally mind because I enjoy the process, but we have to plan for a long journey.
I taught her to give me enemas using the start/stop technique I learned from The Optimal Health Network's videos. When I went down on her, we really extended this. Initially, I asked her to hold off giving me water until she started really feeling a stirring, which was usually 20 minutes or more into the process, and that ended up being a cool to cold enema for me, especially at first.
So then we evolved into her giving me a little water periodically the whole time, but she found that distracting and, so, took even longer to climax - probably over an hour in some instances. Sometimes that was longer than I was able to hold a 3+ quart enema, and the time she needed got longer as we aged and hormone levels receded.
After a few frustrating instances of me having to bail to release my enema without either of us having climaxed and, worse, a couple of messy accidents when retention nozzles failed, we decided to decouple my enema from her orgasm(s), and we shifted to our current standard operating procedure.
Writing about what we used to do, coupled with the great improvement in her sexual response from some hormone therapy she's currently taking, kind of makes me want to try it again, though.