For me it was a friend-of-friend situation. My friend (the guy I was seeing at the time) began introducing me to some of his friends, one of whom was an enema enthusiast wanting to be a naturopath. As the night wore on, someone brought joints and we all started smoking outside. Well, my guy disappeared into the house for a while with the aspiring naturopath. I didn't think much of it, as some of the other guests themselves started leaving. It wasn't much later after my guy disappeared that the would-be naturopath emerged from the house, came over to me, and told me to go with him. Slightly high, i followed him inside and saw my guy relaxing on the couch after having taken a surprise enema of a homemade herbal recipe -- that's why he disappeared with his wannabe naturopath.
Well, the naturopath (now the friend-of-friend situation) wanted me in the bathroom so he could use up his handcrafted herbal solution -- he was very proud of it. I let him fill me, but it was an entirely awkward and uncomfortable situation. He used a handheld bulb and must have carried it out with him because he was stepping out of the bathroom as he was pulling the bulb from me (and no, I hadn't farted in his face or anything). I didn't even try to hold the enema -- i got up from all fours to sit my ass down on the toilet to expel -- that's when I noticed the bulb was gone. Good thing I didn't have to pass much, so I hurried up and got dressed. He was outside the bathroom door waiting for me, bulb still in his hand.
So he of course watched me receive it because he gave it to me -- no problem with that. In retrospect, I'm glad he left the bathroom as soon as he did, because it was already a strange night which could have been really weird if he remained in there while i sat on his personal toilet releasing his handmade enema.
As for my guy, he was almost asleep on the couch by this time. We left then too and never spoke further about our night of surprise enemas.