Diddy's former girlfriend Cassie spoke about the so-called 'freak off' parties during her testimony at his trial.

Casandra “Cassie” Ventura is expected to take the stand in her ex Sean “Diddy” Combs Manhattan sex-trafficking trial on Tuesday, with testimony that’s poised to be a tell-all accounting of his alleged pattern of abuse. Here’s what to know.

Ventura, who is one of Combs’ accusers, delivered a harrowing account of her relationship with the music mogul, which prosecutors say involved coercion and abuse. Her testimony, according to CNN legal analyst Jennifer Rogers, is central to the prosecution’s case, as she provides insight into the alleged exploitation and abuse by Combs.