There's a side activity called MesuKing. It's a card game where women in sexy bug costumes fight. At the end of each match the camera pulls back to show beetles watching the match.
In various attacks enemies are implied to lose teeth, especially when you attack using either nails or firecrackers, with said attacks focusing almost entirely on oral trauma. When using pliers you can also pull the teeth of enemies.
Substory 2: An assassin disguises as a stripper in order to approach his target. A character shouts "It's a man!" before the assassin takes off his wig and shoots someone.
Substory 32: A trans woman challenges Kiryu to a fight, while she is not misgendered, it's implied Kiryu is only willing to fight her because she used to be a man.
Substory 35: Kiryu has an encounter with a woman, but fights him upon learning he is a cross-dresser trying to scam him. He is later joined by his sister, also a cross-dresser who Kiryu mistakes as a man
Majima Everywhere: In Club Shine, Majima appears in drag under the name Goromi, in hopes of initiating a fight with Kiryu. The latter however decides to sit down and chat with her, like he would with a regular hostess. They do end up fighting after the session, after Goromi suggests they go on an after-hours date, which Kiryu refuses, telling her "you're not even a girl" after Goromi accuses him of "breaking a girl's heart"
The game is set in a red light district so there's that in the background. There's a gentlemen's club called Asia that is completely optional (though you do have to go there for a substory and a Majima Everywhere mission). If you complete the storylines for the hostesses, you are shown softcore p*rn videos that can be skipped.