In the Kazarimado series:

V.1 - Kazarimado
The story is set in 70's London. There's a strange male prostitute who sits in the rounded turret window of a hotel. Passerbys who show an interest are instructed by his pimp in the street to go to room 17 and say they're checking accounts for the gas company. People come to this window boy for consolation and this is what he does.

V.2 - Madobe no Otoko

V.3 - Aoi no Yoake