The nudity at the brothel last about 2 minutes in a 1 hour show. No sex scenes.
Prince Oberyn brought his mistress the bastard Ellaria Sand to pick both a male and female prostitute. They are both bisexuals from Dorne. In Westeros Dorne is like Sodom. This scene was meant to illustrate those points. How Dorne and its people differ from the rest of Westeros.
People who call GoT porn are either ignorant or stupid.
I find it hard to fap to, but I manage anyways.