The "Umbrella" singer and her 19-year-old boyfriend – who has been charged with felony assault and making criminal threats following his alleged assault on her last month – are said to have filmed themselves engaging in a series of "kinky" acts.
A source told America's Star magazine: "Chris and Rihanna enjoy an aggressive love life that would shock many people. Rihanna loves dressing up – including as a dominatrix – and role playing. They both have kinky sides."
Rihanna - who reconciled with Chris shortly after their altercation, but is now said to be taking time away from him to contemplate their relationship – has become increasingly concerned the footage could be made public and is desperate to keep it under wraps.
The source added: "Rihanna has no issues with her sexuality. She can be really out there. But she'd be mortified if her friends and family found this out."
"Rihanna isn't always the little goody-two-shoes everyone thinks she is, and Chris doesn't want or need another scandal."
Chris is accused of hitting, biting and choking Rihanna until she was unconscious in his rented silver Lamborghini.
The pair are not the first famous faces to film their bedroom antics, Pamela Anderson and Tommy Lee's homemade video was famously made public when their home was burgled.
Paris Hilton, Colin Farrell and Tom Sizemore have all also appeared in sex tapes.
Meanwhile, Rihanna has been spotted cozying up to "That 70s Show" actor Wilmer Valderrama at Los Angeles nightspot Les Deux.
An onlooker said: "I couldn't tell whether they were kissing or just talking really close together, but something was definitely going on there."
