Who? Rock & roll guitarist, singer, songwriter, legend.
Real? Probably real. The tape exists, but the man can’t be definitely identified as Chuck Berry.
This video recording circulated underground for years, and was eventually released by a tiny video distributor under the title Chuck Berry’s Home Movies. It shows a man who sounds a lot like Chuck Berry pissing on a young woman in a hotel room bathtub while talking dirty and farting loudly. The man’s face is never visible, so there’s no way of knowing if it’s really Chuck Berry.
There’s a Wikipedia mediation page where users debated whether to include info about the Chuck Berry pissing video. They apparently decided to delete it.