vinegar stroke

== English == === Etymology === (This etymology is missing or incomplete. Please add to it, or discuss it at the Etymology scriptorium.) Perhaps from the strained facial expression of a person ejaculating, like that of somebody tasting sour vinegar. Compare sourfaced. Perhaps likening the fast strokes to shaking a vinegar bottle. === Pronunciation === === Noun === vinegar stroke (plural vinegar strokes) (slang, chiefly in the plural) During masturbation, a fast stroke of the penis just before ejaculation.