Of all of life's romantic pleasures, to me the most erotic is passion. A lot of people mistake lust for passion.
Real passion goes beyond superficial sex.
It totally inhabits the individual, rendering them helpless. Real passion creates a heat wave that sears through everything else. It's extremely difficult to capture honest passion on film, and that extends to the world of adult movies. More often than not passion is part of the act. It must be difficult, if not impossible, for an actor to create something so raw and personal.