Shaking out a Sarson's

A phrase to imply a male who is masturbating. This includes making a 'vinegar face' at the end, producing the classic sound of vinegar bring shaken out of a small hole, and releasing potentially eye-watering goods.

"I was just in the toilet shaking out a Sarson's"

"I shook out a Sarson's all over their face. They were crying for days"