Ah, the danger of writing sex scenes in first-person . . .
True story: Many years ago, I was at a convention when somebody praised me for including a gay sex scene in my most recent story. This puzzled me since I didn't remember writing one (not that there's anything wrong with that). Then I figured it out:
That particular story had been written in the first-person and I guess I hadn't made it clear enough that that the narrator was a woman, so when she hooked up with a guy at one point, the reader had assumed that "I" was also a guy . . . perhaps because the story was by a male author?
Which just goes to show that first-person is trickier than it looks!