A non-standard present participle suggesting the hypothetical action of making something in Flemish style or character, not found in standard English dictionaries.
From a constructed form Flemish plus -ing suffix; similar to how English allows speakers to create verb forms even for words that aren't traditionally verbs.
English is incredibly flexible—you can take almost any noun and add -ing to make it seem like an action, which is why people can say 'I'm Googling' even though Google is a company name!
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