My reading of the scene was that it was a way of contrasting her sexual experience (great) with her IQ (small). Simply put, although she has plenty of experience "doin' it on top", she lacks the vocabulary and the wit to recognise that that's what he's talking about.
Note that she also fails to realise that he's been to prison, imagining that he's been living in a monastery (!?).
This quite a common conceit in Hollywood films and her personality fits quite nicely with the TV. Tropes descriptor:
The Brainless Beauty is rarely the hero; they tend to be foils for
more intelligent (though less successful romantically) characters.
Some are sympathetic good-natured dullards, others are presented as
annoying obstacles for our heroes. Either way expect a smart but plain
character to be left fuming at the unfairness of it all.
A Brainless Beauty — even a sweet-natured one — is unlikely to be the
serious love interest of The Hero. In fact they make a natural
Romantic False Lead. It can happen though if the Beauty shows some
form of Hidden Depths.