This is already the third doujin featuring Raise and Mikoto, the shy dork with a curved penis and the tall gallant rich girl with a proclivity for anal. This time, we also have a third wheel in the mix: a hot older mysterious woman who may have previously been a recurring background character.

Put those three in a naked bathhouse and you got yourself one steamy futanari extravaganza.
*All characters depicted in this work of fiction are adults, regardless of their visual representation or textual description, and are not based on any real person*