Never applied too much in the way of mental gymnastics to this (like most things my wife would say). A gentle to moderate whack to the Allen wrench with a rubber mallet has always worked for me.
It did take a while to interpret the OP though. “Slamming the stem” for a lot of people means setting your stem as low as possible for a lot of saddle to bar drop so I was confused.
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N = '96 Colnago C40, '04 Wilier Alpe D'Huez, '10 Colnago EPS, '85 Merckx Pro, '89 Merckx Century, '86 Tommasini Professional, '04 Teschner Aero FX Pro, '05 Alan Carbon Cross, '86 De Rosa Professional, '95 Gios Compact Pro, '95 Carrera Zeus, ‘81 Masi Gran Criterium, ‘81 Merckx Pro, ‘89 Cinelli Supercorsa, ‘83 Bianchi Specialissima, ‘VO Randonneur, Ritchey Breakaway Steel, Rivendell Rambouillet, Heron Randonneur, ‘92 Ciöcc Columbus EL