The whole movie is about a sexual relationship between an adult woman and her teenage stepson. The boy often pressures the woman into sexual acts into which she "gives in". She implies having been raped as her first sexual experience. All times but once her husband and the mentioned boy essentially just use her body, finish, and thats the end of sex (there is also no communication or her doing anything, she just lies there while they do things to her, even when in the one scene she gets head and then orgasms from penetration). The one sex scene between her husband and her is him touching her, immediately going to penetration, finishing, and rolling off - she responds positively to this.