Hoping someone recognizes this...
The dude who lives upstairs in the apartment dropped something on the balcony bellow, to retrieve it he jumped down. By doing so he ends up witnessing a business lady masturbating. Don't know what happens next, but the boy (I believe he is in high school) starts a sexual relationship with her. (Also the dude acted remorseful and innocent, which was far from his true personality.) The woman grew to love him, well care for him. But the guy wasn't interested in a relationship, he just wanted to have sex with her. He even let her know that he had other lovers, and she wasn't the only one. The lady did a 180 on her personality, since she wanted the guy and he wouldn't be hers. She literary tied him up to her bed just to keep him with her, and since the guy lives with his mom, and in the same apartment. The people in the apartment started gossiping on his disappearance, stating that he probably left with a woman.
-It's a one shot manga
-The lady had long dark hair and smokes
-The guy has light colored hair and is younger than her
-The woman found out about his true personality, when he took a phone call from one of his other lovers in front of her.
-He had a ruse with her, whenever they had sex he acted like he was in love with her and cared for her.
-I believed he was knocked out, and you don't see the aftermath of that scene. Skips forward to her returning from work and hearing the ladys gossiping about the dude. And she returns home to an angry/tied up guy in her bedroom.

Fingers Crossed!.
(The sex scenes weren't descriptive Btw)

i'm sure it was this >> 12-sai kara no Himitsu 😕

[img]http://i67.tinypic.com/2vbook7.png[/img]