You know, if you pretend that sparring is code for sex, that whole "Diana the virgin" thing gets rightfully blown right out of the water. And how else would an Amazon warm up for sex anyway? Go out to dinner? Not unless she caught and cooked it herself. (I wonder if an Amazon would have difficulty, culturally, respecting someone who couldn't compete as well as them. At the very least, I don't think Diana would be interested in someone who couldn't debate or reason well.)
Now I wish I could think of a canon incident of Donna and Kory sparring while Diana watches, because that would be really kinky in retrospect.