Identify hentai manga

[Penguinato]

As far as i remember a loli girl went into a mens bath. Knowing what it is then one of the men noticed her and sat beside her to do lewd things. Then they proceed to an open bath onsen/hot spring to do it further there. I remember they did it underwater as the little girl slipped. After that they went into a little exhibitionism they did it out in the open. TIA for answers