Spanking the Monkey (1994) on Netflix

Raymond Aibelli is a promising medical student ready to begin a prestigious summer internship. But Susan, his mother, is immobilized by a broken leg, and his father Tom, a travelling salesman, makes Raymond stay home and take care of his mother, an attractive though unhappy woman. His mother's condition leads them to a degree of immediate physical contact which Raymond finds disturbing. He soon meets Toni, a high school girl, but his sexual impulses are increasingly confused, especially since he is still upset over losing the internship.