I never thought I'd really care for 1st person. But, I've found that more and more often, my short stories (mostly dark fantasy, with the smattering of fantasy), that they more often than not wind up in 1st person. I'm actually tinkering with a fantasy novel written entirely in 1st person, but from multiple narrator's POV (all are easily identified as being a seperate narrator). Some will even tell hearsay stories in first person, using 3rd person narrative (that is, relaying to someone else, the reader, what Fiticus told them about another event).
I haven't written much seriously in the way of erotica, but the two short stories I just wrote both take place in 1st person.
I think 1st person gives more a sense of intimacy to a story, which is really what you're aiming for in this genre, IMHO. Sort of like someone's best friend telling them all the naughty details of an experience they had first-hand.