By recognising the limitations of formal sex education, young people are able to seek out alternative material, gaining informal sexual knowledge through their own means and through a wide variety of sources. This paper derives from part of a larger study centred on feminism and heterosexuality in practice which features 17 feminist-identified women (age 21-59) who engage in sex with men. Offering a multi-generational perspective, in which participants experienced sex education and gained informal sexual knowledge from the 1970s to 2000s, it identifies important synergies regarding the continued insufficiencies of formal sex education as well as the role that sex-positive feminism has played in gaining informal sexual knowledge throughout the last 40 years. Motivated by overwhelming themes of protection and prevention, the informal sexual knowledge these women gravitated towards approached understandings of sex and sexuality from a critically informed, sex-positive, feminist framework, that includes the potential and possibility of female pleasure and desire. In many cases, seeking informal sexual knowledge emerged alongside young women's early associations with feminist values and identities. Findings point to the important role of feminism and sex-positive texts in young women's reflections on gaining informal sexual knowledge.