The boy and a girl his age sneak up a hayloft and watch the teen girl have sex with a man, afterwards the little girl makes fun of it by emulating the sounds and rubs herself all over.
The boy has a 'wet dream', where he's a knight rescuing the teen girl, who's been tied up with tarnished clothes and her breasts exposed. As the boy unties her and starts to hug her semi-naked body, he wakes up. Realising he's had a wet dream he punishes himself by slapping his penis with a wet towel.