A woman doctor is giving the girl a medical examination when the girl reveals to her that her brother is concerned about the state of his genitals, so the woman has him climb up on a table and show them his penis for examination [not shown]. Includes rear nudity of the boy (with the little girl clearly seen looking at his front). The girl makes a reference to his times of arousal by saying [subtitle translation] "He's grown a bone in his willy".
A little later this same woman is having a bath, when the boy walks in and looks at her body. She invites him to put his hand into the water and touch her, which he does.