Title: Ona Ken!
Original title: オナけん!
Length: Short (2 - 10 hours)
Year: Japan 2011-10-28, English Version 2015-08-20
Developer: FruitsJam
Publisher: FruitsJam
Language: English
Voice: Fully voiced

Description:
Kasukabe Nao, who masturbates every day, decides to form a club to discuss masturbation, so as to get new ideas for the ultimate masturbation. She forces her *hood friend, Natsuigawa Hibiki, her classmate, Akiru Norika, and an upperclassman, Fuyutou Mako, to join her in the club.

Important:

1. No need to install.

System Requirements:
OS: Windows Vista/7/8
- When playing on Vista/7/8, use the account with administrative privilege.
- This software is arguably playable on WindowsXP/Windows10, but we can’t warrant it.
CPU: Pentium4 2.0G or more
Memory: 512M or more
HDD: 1G or more

Source: From the game readme file.

Screenshots: