Newmanoid Cam: Cam Castin, Cosplay Roshutsu Kenkyuukai Recommendations
Both of these short hentai feature a cosplayer that attracts a lot of attention. Otaku then ask the cosplayer to pose for a photo shoot, and afterwords they whip out their dicks and cum all over her.
The heroines are cosplaying for a photo shoot, but as they continue to do poses, things went over the line. So both hentai are about attracting attention first, then it quickly escalates before you know it into some kind of mindless gangbang.