They only sang karaoke. Because the boss said that "After" doesn't necessarily mean love hotel or sex that he decided to go. And the seme knew that he was gay so there's no way he had sex with the woman.
That's what I understood with the way things went in the story. (●'◡'●)ノ
And about the baritachi... the boss is only explaining to him that he's gay and he managed to be the #1 in the club even without sleeping with women and there are lots of ways to earn money and boost your ranking depending on their service.
Wait so the Young Master slept with the woman who ask him the "After"? (Didn't understand, specially with the suddenly Baretachi speech)