Back when we were doing the occasional enema, my wife would once in awhile mention that she was constipated and thought she might need an enema. Needless to say, that was all it took to get me going! My giving her an enema inevitably left both of us highly aroused and led to great mutually satisfying sex.
As much as I wanted, and made my desires known, she never initiated a session in which she took charge and gave me an enema on her terms. I wanted to be completely dominated. When I wanted/needed an enema, I would ask her to give me one. She never refused, but they were pretty matter of fact. At most, she would provide a little extra stimulation by saying naughty things, unnecessary touching and handling of my boy parts, and moving the enema tip around and in and out "to get the flow going." Whether she got aroused or not, she took for granted that she was going to have to take care of my hyper-aroused state. One orgasm and ejaculation was never enough after an enema session.
For a long time after we stopped actually doing enemas, occasionally when she masturbated me, she would heighten my arousal by talking about the very scenario I had so desired but that she had never actually done. That never failed to produce a intense orgasm and powerful ejaculation. It is hard to say why the fantasy and reality never met. She is not a prude or opposed to a little kinky activity, but my particular enema fantasy was never indulged.
Recalling those days makes me think, maybe, an enema or, at least, an enema fantasy and handjob might be just the thing...