Green’s Dictionary of Slang

(US) a rapid decline, usu. towards ultimate disaster; esp. in phr. on the toboggan/tobog.

1896		H. Blossom Checkers 41: When a fellow ‘hits the toboggan,’ he gets to going down mighty fast.
1908		Sporting News 27 Feb. in Fleming Unforgettable Season (1981) 23: McGinnity began to hit the toboggan in 1906 [...] Last season his efforts at times were painful.
1913–14		Van Loan ‘For the Pictures’ in Taking the Count 337: He’s on the toboggan for fair. I guess he never got over that quick trimming you handed him.
1920		Ade Hand-made Fables 38: [He] knew that he could put W.S. Hart on the Tobog if he ever got a whack at the Pictures.
1931		K.C. Star 31 Oct. 12: With everything else on the toboggan how can you fancy wheat going up? [DA].