The whole movie is about high school kids having sex but it is always implied, never shown.
A girl and a guy make out, she is only wearing a bra and pants.
A girl is shown trying on several sets of bras and panties. No nudity but there are several close ups of her chest and rear.
A girl and guy make out in a bed. He takes off his shirt and she straddles him. She takes off her shirt and is shown only wearing shorts and a bra.
Names in "the book" are read and a page is shown superimposed over lingerie being thrown in the air.
A girl is shown using a vibrator (not graphic, just implied) followed by a massaging showerhead and a carrot. She tries getting off on a washing machine. Her butt (mostly bare) is shown as she goes upstairs afterward.
A guy pleasures himself with paper mache.
Three guys are blindfolded and lured into the pool area. The girls have them take off their clothes and then the girls leave. The guys don't know the other guys are there and, still blindfolded, start touching each other. The girls take pictures before the guys figure it out and the pictures are posted all over the school.
A guy masturbates in his bathroom several times (again, implied not explicit) and fills an ice cube tray. Later, the girls spike the punchbowl with Viagra and unknowingly with the special ice cubes and give drinks to the guys. Some of the guys go to the hospital with erections that won't go away. The others vomit when they find out what was in the ice cubes.
A girl masturbates in bed. Her hand is down her shorts so nothing is shown.
The lead couple finally has sex but are shown fully clothed.
Two girls make out.