Twitch targets butt streams with new rule banning 'content that focuses on intimate body parts for a prolonged period of time'

It's best if you imagine Twitch's latest rules update being read by a downtrodden, barely present spokesperson. 

"Content on Twitch is always evolving," they mutter, unable to recall how many versions of that statement they've composed before. "And we want to make sure our rules work as intended and keep up with emerging behaviors." 

The behavior that emerged this time is streaming games on butts. That is, using one's posterior like a green screen, overlaying a gameplay feed on it.