As a teenager I was not occupied with sexual fantasies for whatever reason. It wasn't until I was 21 I had my first sexual encounter and it wasn't all that good. Probably after the age of 25 sex kicked into high gear for me.Honestly, just remember yourself as teenager, and the what to do becomes, I think, more obvious.
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It wouldn't have mattered what anyone told me about sex my natural drive controled me.
I think each teenager needs to be handled differently. All given the knowledge so that they know what's in store for them but you don't suggest any specific method of sex.