As part of the Erotic 90s season of Karina Longworth's excellent 'You Must Remember This' podcast, the episode that dropped today is all about M in 91-93.
Both Erotic 90s and Erotic 80s are really great, excellently researched series about sex and American culture.
SEX, Erotica and Body of Evidence
http://www.youmustrememberthispodcast.com/episodes/madonna-sex-erotica-and-body-of-evidence-erotic-90s-part-10
If you've never heard of it, also try this two-part episode from 2014:
Madonna, from Sean to Warren
http://www.youmustrememberthispodcast.com/episodes/youmustrememberthispodcastblog/madonna-from-sean-penn-to-warren-beatty-part-1
http://www.youmustrememberthispodcast.com/episodes/youmustrememberthispodcastblog/ymrt-15-madonna-from-sean-to-warren-part-two