I Can't Believe I Slept With You! manga volume 2 features story and art by Miyako Miyahara.

Koduka Chiyo, twenty-four years old and unemployed, provides “favors” for her landlady in place of her overdue rent. At least, that’s how their arrangement was supposed to go. But as time passes, the distance between the two women has dwindled. Just when things are getting interesting, an older beauty moves into the apartment complex where they both live! What will happen now?!