Lewd Service, hospitality in the form of erect penises… Why is it so good!?

(Source: Coolmic)

Note: Originally serialized as a web manga under the title Chin Pub!: Ano Musume wo Ikaseru no ga Ore no Oshigoto (ちんパブ！～あの娘をイカせるのが俺のおシゴト～) with each chapter split into 3-4 ‘episodes’, resulting in a total of 91 episodes.