This study consists of a quantitative and qualitative analysis of sex in the 50 most popular films on release in North America between 2011 and 2015. It emerges against a background of discourses on sexualisation and pornification in social scientific and public health research, on the one hand, and a rhetoric of transgression in film studies, on the other. It bridges the gap between these disciplines, between theoretical frameworks, research practices, and methodologies, by employing quantitative and qualitative methods to generate a substantive theory of sex in the films studied. The method consists of selecting films for analysis based on financial data available for films on domestic release, on home entertainment markets, and Western film markets; identifying sexual content by analysing portrayals and spoken references; and using grounded theory to generate the substantive theory. This study establishes that the 250 films selected for study account for 7% of films on domestic release but 70% of ticket sales for films from 2011 to 2015. At least one scene featuring sexual content, either depictions or spoken references, occurred in 96% of films studied. Nongraphic sexual content accounted for 69% of sex scenes. It also found that the prevailing discourse on physical intimacy and sex occurred between characters who are not in a close personal relationship. The substantive theory encompasses the processes of discipline and disclosure that pervade the discourse on sex and physical intimacy as characters feel obliged to reveal their desires and sexual histories, and these revelations are subject to validation, approval or influence from others. These processes reveal the ongoing regulation of film sex. Exclusion emerged as the primary mode of representation of non-heterosexual sexualities. Repudiation constitutes the secondary mode. The analysis also reveals that portrayals of kissing operate as a visual grammar that legitimates and valorises heteronormative values.