Reading the rules, it says "when you have sex..". Remember, you don't have sex with someone if you rape them, rape is something you do to someone, therefore sex is consetual. Rape is never mentioned.
I think the player (or you) mixed the sex move with the "turn someone on" move. You can turn anyone you want on (if you roll the dice right). That just means they get turned on, it doesn't imply that they must have sex with you, just that something you did turned them on.
You can't control what turns you on. You can't control your hormones, something that goes double for teens (and pregnant women, if my wife was anything to go by). What you do control is how you choose to react to being turned on.
Look at real life. I pass pretty girl with a nice smile, or a cute butt, or a nice chest, or sparkling eyes in the street, hell yes I can get turned on (and I'm 35 years old, far from a teen). Doesn't mean I jump their bones right then and there, or later for that matter. It just meant I got turned on.
As for the fey sex move, "when you like naked with another", as I interpret it, doesn't necessarily mean having sex, although it's certainly possible that that's what happened. The way I read it is "when you're physically intimate". After all, when you lie naked with someone, it's not necessarily sexual, you can have sex without it being intimate, but when you lie naked with someone, you're vulnerable and close to them. You bare yourself open to them.
Hope you found my musings useful.