I have had lots of truly random sexual dreams in my life, some of which made perfect sense with my identity or desires, some of which were completely repulsive, and some of which were just bizarre. Sometimes I'm male, sometimes I'm female, sometimes I switch partway through, or change places with my partner(s?), or one of us turns into a different person. I honestly don't think it means anything, usually. I've always figured that dreams are just the brain tidying up from the day, and constructing vaguely connected stories out of the elements it finds lying around. Sometimes that's a goat, sometimes it's Angelina Jolie. If I tried to make sense of it all I wouldn't have time to talk about anything else in therapy!
The dreams that do mean something, whether sexual or other, I usually realize when I wake up-- it's not the dream that has the meaning, it's the insight it gives my waking mind. No insight, no meaning.