Courtney Stodden -- My Solo Sex Tape Self-Pleasured Tens of Thousands

Courtney Stodden's sex tape broke records for masturbation ... TMZ has learned.

Vivid Entertainment honcho Steve Hirsch tells TMZ 10,000 new customers signed up at $39.95 a pop to watch Courtney stick an ice cream cone in her hoo-ha. We're told another 20,000 existing members forked over the cash. That's a skosh under $1.2 million in 24 hours and Hirsch says it's already the most successful self-pleasure video and it's tracking to beat Farrah Abraham's back-door vid.

On top of that, 2 million people jumped on the site to view the 5-minute trailer.