London Flog 

The urban practice wherein a man strolls the streets, fully clothed and in a belted trench coat, and slowly but covertly, though a side pocket, masturbates himself in the presence of fellow pedestrians and pasers-by. The benefit of the act is sometimes claimed to be expediency, but more likely is the ability to "get away with it," especially when ejacualation is achieved but not revealed.

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"Why do you say Geoff's a wanker?" -- "I mean, literally, man. I ran into him on Halsted and he had just done a complete London Flog."

"How could you tell?" -- "Well, partly by the refreshed happy-ending look on his face, but mostly by the stain he had made on his trench coat below the buckle."

"Ewww . . . well, at least he kept it in his pants."

London Flog by al-in-chgo March 20, 2011