His Noona gave him the most realistic information about s**. His aunt and his friend caused things to get twisted from the start (in paricular, in my opinion, whenever a person is taught that something is 'evil' this causes them to have a misinformed view and fear of that thing, that's why I believe that kids need to be provided with health education, financial education etc. from reliable sources).
But what is really interesting is that all of them told him that s** etc. are things you do with someone you like/love and that its something that's ok and that healthy people do. So now, he seems to be motivated to have s** with all these females because he likes them. And, in my opinion, because his feelings are geniune toward them when having s**, that comes across to his partner and this is part of the reason why they feel like the s** is 'amazing'