Based on the CG collection by Churu Bitch Churu Churu (ちゅるびっちちゅるちゅる).
On a sunny holiday he took a drive to a certain rural village and awaiting him in an open-air bath were, unexpectedly, three little loli girls all in naughty outfits.
The three introduce themselves, and the service begins...
(Source: DLsite English, edited)