Consider it normal curiosity, we all went through it. Both of you together explain the difference between lust and love, compatibility, marriage and divorce. Explain the difference between fantasy and the real world (ugly people and BO). Then order him a subscription to Playboy.  He'll wear it off, or at least get some serious blisters trying. If all else fails, introduce him to the preacher's daughter.  By the time he's my age he might be able to meet one on the girls that was in one of his old Playboy issues.  And that will make it all worthwhile, huh, Stevie?