Neighbors get to go to sleep and wake up to the sounds of them banging all the time. I wouldn't be surprised if they were all constantly horny as a result.
If you want another manga where the characters rawdog every chapter then read a story of a very ordinary couple or actually since it's a sequel first read a story of a man and a woman and when they sleep together money appears
Given that 90% of Japanese women will put on makeup for leaving home for any reason (corner store, drop trash, whatever), this seems legit (although artist skimmed over the makeup bit maybe)