From Renta!:

Novelist Hiroyuki has a habit of taking in stray cats. One day, at a bar, he meets a guy called Haru who's as miserable as an abandoned cat. Hiroyuki can't help taking him home! Despite Hiroyuki's innocent intentions, things take a naughty turn when Haru mounts him saying, "I wanted to thank you for today." For all his enthusiasm, though, it's obvious his tushy has never been touched before... The next morning, Haru's gone. Will he ever come back? Will Hiroyuki ever see him again? As he waits for Haru to turn up on his doorstep, Hiroyuki comes to realize he's gaga for Haru. Trials and tribulations abound as he tries to get this cat to love him back... This manga is chock-full of steamy nights and pillow talk between a struggling novelist and a freeloading homeless kitty-boy!