Dreams.

Interesting, very interesting dream. But I disagree with you about it being nonsense. In this case, everything is quite simple and clear. In reality, you really want to have sex with an androgynous alien, as you put it. However, it seems that your Super-Ego has pushed this desire deep into your mind (because in the dream, you felt disgusted by it). I don't know exactly why this desire suddenly appeared, but I dare to suggest that you have recently lowered your level of sublimation, and your Id has peeked out from those very depths.
Since it is impossible to satisfy such an exotic sexual desire, I would advise you to increase your level of sublimation back to its previous level, or, as an alternative, look for a girl with an unconventional appearance.