MIRD-210 Part-time job coworkers miss the last train and stay over, leading to a harem creampie orgy

At his part-time job, the protagonist is useless, but his senior female coworkers invite him for drinks and miss the last train. They end up in his room, and when they get drunk, they force his pants off and ask to see his penis, leaving him fully erect. Then all of them compete for him with excitement, and the night becomes a milk-covered, harem-style sex session until morning. The four women include Tsubaki Rika, Sachiko, Nagisa Yukino, and Tanaka.