I think my choice would be Spencer Tracey in Look Who's Coming to Dinner. He's arguing with his wife played by Catherine Hepbourn about their daughter's choice of fiancé who happens to be played by Sidney Poitier. He has a drink of whiskey beside his shaving mug and he mixes them up. Very funny moment in a tense little scene.
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PS I'm not sure if that's a straight or a DE actually. I guess that's one of my favorite wet shaving scenes at least.