Malcolm told the story of his and Dolly's year-long affair in Dolphin Love, a new film which premiered last week at the Slamdance Film Festival in Park City, Utah.
In the film, Malcolm opens up about his first job as a freelance photographer at Floridaland, a tourist attraction disguised as a marine park.
It was here that he first met Dolly - and fell victim to a fairly aggressive form of dolphin seduction.
According to Malcolm, Dolly would often rub herself against him suggestively, or gently run her teeth down his arm.
"I started rubbing her along her back, working my way to her flukes – her tail"
He said: "[She] announced her intentions to me by positioning herself so I was rubbing against her.
"I started rubbing her along her back, working my way to her flukes – her tail.
"And as I was rubbing her and moving my hand towards her tail, Dolly was slowly rolling around her long axis."
Things apparently get a lot more graphic from this point, with the phrase "genital slit" used as an animated interpretation of the sexual encounter plays out on screen.
Malcolm, who had access to the dolphin pool after hours in his role as a photographer, found it all too easy to procure time alone with Dolly - and insists that their relationship was so much more than sex; it was emotional too.
You can watch a short teaser for the documentary below:
Malcolm has claimed on numerous occasions that the relationship was consensual - and that it lasted a year.
Speaking with the Daily Mirror in 2014, he said: "There's something quite transcendental about making love with a dolphin.
"The dolphin is very aware, the dolphin is an intelligent and creative creature and making love is a consummate act."
Bestiality was not made illegal until 2011, so Brenner and Dolly's relationship, which occurred in 1971, was not a criminal act.
If you are interested in watching Dolphin Lover in full, it's worth checking out the movie’s web site and sign up for email updates.