Ex-Dolphins Coach Says He Used Cocaine '8-9 Straight Days' Before Snorting Video

The Miami Dolphins assistant coach caught blowing lines is coming clean on his addiction -- admitting he was hooked on coke before his snorting video ... and vowing to stay sober.

In an interview with NFL.com, Chris Foerster says he was introduced to cocaine in 2015 ... and was using "eight or nine consecutive days" before filming the video he sent to Kijuana Nige -- a woman Foerster met in September.

Kijuana released the video on Oct. 9 -- forcing Foerster to resign from the Dolphins on the same day.

But the ex-coach says he's glad he was forced to confront his demons ... 'cause it led him to a 60-day intensive rehab program.

"I knew this s**t was out of control," Foerster said. "It's what I needed."