The first man who I had anal sex with as well as enjoying giving and receiving enemas from was my late fiancé. I have described in detail, to the best of my recollection, our first time together (after months of talking online and messaging and Skyping, since we had been introduced by a mutual friend about a week before he was deployed overseas; we knew that we wanted to get to know each other more right away but there had simply been no time then). First came anal play, then a large enema, and then he proceeded to fuck it out of me. That date lasted for over 48 hours and we were inseparable ever since, and until the very last day that we were physically together, and then until our last phone call before he was killed by an IED.
That first date set the tone of our relationship. The fact that we had both wanted to find someone who would understand us and our kinks but had been unsuccessful until then; the fact that we immediately felt like we had known each other forever and that we could be ourselves without fear of being judged; the fact that we instinctively knew each other’s bodies and needs. We had both been married before and neither of us had experienced that level of closeness and intimacy with our spouses, or had even been able to really explore our anal erotic desires with them except for very briefly, and without an inkling of a positive response.
We were not together very long, in the grand scheme of things, in absolute terms, but just about every day that we were lucky enough to share a house, a room, a large bed and a lovely bathroom, we made the most out of each of those things and savored each other. Maybe we knew, subconsciously, that we had limited time on earth. I think about it often and I come to the same conclusion: we had a very deep, extremely strong desire for each other and an insatiable bond for everything about each other. He was a very smart man but he was not as articulate as the type I used to go for, or as I am. He was very spontaneous and direct and his actions spoke louder than words. We would talk and laugh and talk and cry, too, sometimes, but we would communicate equally well when we were giving each other the most amazing sexual pleasure either of us had experienced.
Technically enemas came before anal, but it was a matter of a couple of hours at the most, so maybe the best answer to the OP’s question is that they pretty much came at the same time (and so did we, pun intended). There were times when he would fuck me vaginally from behind while holding a nozzle deep inside my ass. There were times that he would first fuck my ass then give me a couple of large, hot and soapy enemas and fuck me again as I was expelling each, edging me at the same time. I pegged him and did similar things to him, too. He was much better than me at taking even the roughest of enemas and I derived pleasure in seeing how much he could take and hold while being eaten or teased or edged or pegged before he would lose control in more ways than one. I wish I could remember what happened first -him being given an enema or him being fucked by my fingers, fist or strap on, for the first time.
Ultimately it didn’t matter. What mattered and still matters is the intimacy and comfort that are required to share any really phenomenal sexual experience like enemas or anal, and that are so hard to find (but so incredibly good if one does find them).