Sook Yin Lee masturbating from the movie shortbus.  She masturbates frequently in this movie, just diddling herself to death over and over.  Can be downloaded at Soloscenes.com

Sook Yin Lee masturbating

Sook Yin Lee masturbating

Sook Yin Lee masturbating

Sook Yin Lee masturbating

Sook Yin Lee masturbating Shortbus masturbation scene

Sook Yin Lee masturbating Shortbus masturbation scene