Itsu made mo Musuko no Mama ja Irarenai! 4 ~Kyonyuu de Kawaii Kaa-san no Oppai ni Tsutsumarete Ippai Amaetai!~Forum

Hello VoidEnd,

Inside the archive, you have a folder named "nodvd", with a folder and a file named musu_mama4.exe.
Copy those files and paste them into the folder DATA where you have installed the game, replace existing files.

If you have an antivirus, you may have a notification about musu_mama4.exe, so you have to add an exception for this.

After that, run the file musu_mama4.exe (data folder)