Every alpha-male chest beating politician has a face in need of a good slap ... "
Charlie Chaplin
alpha-male( gorilla) chest beating /pounding/thumping
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This is a warning signal to the younger gorillas to back off or they will be engaged in a battle! Gorillas also beat their chest for a victory, so when they've won a fight, they proudly thump their chests to show their dominance. Although it's not only to do with showing control and aggression.
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It's a combination of two nouns: Backpfeife (a slap across the cheek) and Gesicht (face). Together they indicate "a face that invites a slap." (Cytowic calls it "a face in need of a good punch" – close enough.) With the efficiency of one word, a common sentiment is beautifully expressed.
Backpfeifengesicht ( germ)
Morda prosit kirpitscha