sht.

There they vanish, their fine tones never to be tried more, and ooze through the red-hot ruin, "Hush-sh-sht!"
History Of Friedrich II. of Prussia, Vol. VII. (of XXI.)|Thomas Carlyle
Do' mensh't, shir—I've met goo' many shor' sight peopl'sh morn', bu' you're firsh gen'l'm'sh made 'shli'sht 'pology!
Mr. Punch's Cockney Humour|Various