Translation added. Needs check. Not too difficult. The unmarked text in the corner is the artist's name/signature as far as I can tell. I believe it would be "izuyu" or the artist's name: "yuuzii". I do not believe there is any translation needed for the sister page to this one.
The joke here being that the character is surprised by the spraying of the bidet and quickly stands, slamming down the lid, and shouting "Disrespectful!" at it. This is why the artist draws water leaking from the lid, presumably the character would have slammed the lid while the bidet was still spraying.