When someone has to shit really bad (or has diarrhea) but also intends to do a summersalt and in the act of doing the summersalt they shit themselves (sometimes leaving a trail of shit).
Tanner wasn't feeling well yesterday and he went to do a summersalt but when he did it. he accidently shit himself creating a shitter salt.
Fogey/fogy /fougi/ sl. (early 18C+, orig. Scot) old-fashioned, stuck-in-the mud.
Person with old fashioned ideas which he is unwilling to change: Come to the disco and stop being such an old fogey!
You think me an old fogeyand an old tory, his thoughtful voice said. I saw three generations since O’Connel’s time. I remember the famine. Do you know that the orange lodges agitated for repeal of the union twenty years before O’Connel did or before the prelates of your communion denounced him as a demagogue? You fenians forget some things. (James Joyce, Ulysses. PenguinBooks,1992. p. 38)