The book in question (which does not, in fact, have ninja, cowboys, or steam power) is one of those fantasies where the author takes some very basic ideas from a range of historical cultures and uses them to construct some very different stuff. There is a stalwart and well-thewn hero (of course) and a spunky, intelligent heroine (natch), and they
And they are from very, very different backgrounds. Some of those differences are things they are aware of at the outset, and some of them.... are not.
See, the hero's culture? Part of their big ritual transition from adolescence to adulthood involves being properly introduced to sex. For both men and women. It's very important that the first time be done right for the... um.. introductee.
The heroine's culture is.... not like that. As in, biiiiig emphasis on Pure Virgin Brides of Virginal Purity.
What makes this particular culture clash so funny (and interesting) is the hero's reaction.
I mean, you know all of those heros who would be all excited about having a virginal bride? This guy is not one of them. He literally has no idea what he is supposed to do in this situation.
He cannot culturally parse the concept of an adult who is still a virgin.
It's fascinating, because it's not a situation I've run into in fiction before. I mean, a hero who is more sexually experienced, sure, absolutely-- including heros where their level of experience is more related to their culture than their gender. A hero who realizes the heroine's culture has required she remain a virgin and gets kind of freaked out (and, trust me, based on what everybody else around him says, he is NOT alone in this)? Definitely a new thing.
(which, of course, means my brain is poking at it gleefully even as I type....mwa ha ha)