They invented a new definition of "shrinkage", in reference, specifically, to a penis retracting into the body when exposed to cold water thus making it appear

They invented a new definition of "shrinkage", in reference, specifically, to a penis retracting into the body when exposed to cold water thus making it appear smaller than it normally is. They obviously didn't invent the verb, and I don't think they believe they did, it's a common word in finance. Before Seinfeld nobody would know what you're talking about if you said you were experiencing shrinkage. It's a way to talk about genitalia without being explicit.