A Dirty Alastair is a person that enjoys a colonoscopy far too much for the comfort any doctors or nurses performing the procedure.

Oftentimes they will book unessassary colonoscopies for no other reason than boredom, or to avoid their other personal or professional obligations.
John won't be at the clientcmeeting this afternoon, he's pulled a Dirty Alastair again...Those poor nurses.
by SCKnocking September 12, 2021
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