Want to join? He might've just meant like, taught him pick up lines and stuff. It could just be a cultural thing, something that little kids do over there like go on pretend dates with older ladies to learn, that the US doesn't do.
Want to add to the discussion?
And Killua theorized to himself that Gon "has no idea what the guys were talking about. I don't know about you but I consider it a good thing teaching children stuff to make them feel comfortable with the other sex. Whale Island was populated, and Gon did go to school according to chapters post-anime ending. It's Killua who never had any friends save for Canary, and that's a stretch.