Some references to penises, masturbation, morning erections, watching porn etc.
Two men are shown flipping through some vintage soft-porn magazine showing women posing in skimpy clothing.
In several different scenes, two teenage boys, who temporarily share a room, are shown wearing just tank tops and shorts or just underwear, homoerotically fighting and putting their underwear on each other's heads. They are also repeatedly shown sleeping in one bed.
It's implied (but not shown) that a teenage boy gets an erection after dancing with his male best friend.
A teenage boy strips naked and starts watching some porn movie, thinking he's home alone, but he gets caught by his parents and best friend and the porn he's watching turns out to be gay. No frontal nudity is shown, everything else is.
A teenage boy is shown in hospital wearing just some sort of waist/crotch bandage, as he hurt himself in the area. His two best friends are watching as a nurse takes the bandage off, but that happens off-screen.
A man says that "if a 17 year old boy doesn't wake up with erection, he should come to see a doctor".
A teacher talks to his students about sexual orientations and gender identities.
A male teacher and one of his male students are urinating next to each other. Since the student recently hurt his penis, the teacher asks him whether he still can "use" it. The student, embarrassed, nods.
Two teenage boys wearing only boxer shorts find themselves in somewhat homoerotic situation, while father of one of them walks in and gets all hysterical thinking they are gay.
Teenage girl is borderline bullying three teenage boys.
One of the leading boys has abusive father, who also happens to be his school principal.
A gay teenage boy is caught by his father wearing make up and feminine clothes. The man starts yelling at his son and ripping his clothes off.
A teenage boy punches his teacher in the face.
A sadistic school headmaster hits two teenage boys with a stick over the palms of their hands.
Mandarin Chinese equivalents of words "ass", "jerk off", "shit" and "idiot".
A woman is shown smoking a cigarette.
Some alcohol drinking is briefly shown.
No drug abuse.