smoky seat, n. — Green’s Dictionary of Slang

smoky seat n.

also smoky rocker

[the smoke that rises from the electrocuted victim]

(US prison) the electric chair.

1931		Irwin Amer. Tramp and Und. Sl. 174: smoky seat. – The electric chair.
1936		L. Pound ‘American Euphemisms for Dying’ in AS XI:3 201: Take the smoky seat/rocker.
1949		Monteleone Criminal Sl. (rev. edn).
1962		Ragen & Finston World’s Toughest Prison 818: smoky seat – The electric chair.