Bored at work and want to have a little fun in the office at the expense of your coworkers? Vice president of Tokyo-based web design company LIG, Go Yoshiwara, has shared a naughty little prank that he recently played—and recorded for all to see. As detailed step-by-step on the company’s blog, vice president Go secretly rigged one of his employee’s computer to automatically load and play porn after booting up.

The blog post is titled “A COOL Way to Force Adult Video to Stream on Your PC When It Starts Up” and details how to perform the prank with a PC running Windows 7.

Planning is key and Go writes that if the target’s computer is not already connected to speakers, you should ready a pair, hook them up discreetly and turn the volume up high enough to be heard throughout the whole office.

You will also need to disable that generic Windows startup sound from playing so as not to alert your victim after they boot up their PC.

You can do this through your sound settings, accessed via: Start->Control Panel->Sound.

In the ‘Sound’ tab, uncheck the ‘Play Windows Startup sound’ box at the bottom or select “Disable All Sound” in the Sound Scheme box near the top if you want to be extra safe. Don’t worry, this disables only Windows sounds so the video should be perfectly audible!

After that, you need to download some porn.

Go recommends Japanese site CPZ for some good free clips, though the site is in Japanese and may be difficult to navigate. He also suggested using a clip that cuts the small talk and gets straight to the action so everyone in the area will immediately understand what they’re hearing.

Next you need to register the downloaded video file as a Startup Program.

This can easily be done by dragging the file to the Startup Program folder in your Start Menu bar. One simple click and drag and you have sabotaged your victim’s work computer to display graphic pornographic video.

Of course, the panicked victim could just quickly click the “X” button to close the window before anyone else notices, which leads us to the coup de grâce: be sure to remove the mouse from the USB port.”

This could backfire if the person being pranked has a habit of actually clicking the “Sign In” button instead of just hitting the Enter key after typing in his or her password, but if you can pull it off their reaction will be priceless:

Source: LIG (Japanese)