I Can't Refuse S manga volume 2 features story and art by Ai Hibiki.

Miku’s love lessons with her sexy butler teacher continue. From learning how to seduce a man over drinks to kissing--with tongue--her training with the dominant Kamishiro is teaching her as much about herself as it is about being a powerful man’s mistress. However, when an emergency pops up at her part-time job, suddenly Miku is forced to ask Butler Kamishiro for his help!