Episode 1: A girl undresses in front of a boy (breasts visible). The boy enters the bath where she is (genitalia not visible) and she touches his genitals (only implied). Few sexual comments including breast size. An adult couple has energetic sex where he thrusts her.
Episode 2: A girl and a boy have sex, not so explicit as they're dressed (she's in bras though) and mostly kisses are shown. She appears to be rather uncomfortable during it but he stops when he's told to.
Episode 4: A girl and a boy have sex, not explicit, but breasts are visible for a second. A man and a woman kiss passionately. There are references to infidelity. A man masturbates, clothed, using a doll.