It's August. For Japanese otaku, the month means that the biannual Comic Market, AKA "Comiket", is right around the corner. The event is an opportunity for amateur and pro manga artists to sell their limited edition, self-produced creations.
In the last few years, cosplay has become a bigger part of Comiket. It isn't just the cosplayers who show up at the venue, but those who create and sell their own ROM disks, filled with cosplay images.
After cosplayer Ushijima Good Meat hit it big at Comiket in 2007, she was able to parlay that into internet fame. Ushijima not only made a name for herself, she pushed the envelope. Many of the young cosplayers do, too, hoping to make a splash in nerdom. And making a splash often means to shock and surprise. That's why there are numerous adult oriented ROMs available throughout Comiket.