Green’s Dictionary of Slang

scutter n.²

excrement.

1991

T. Delaney Where We Sported and Played 57: I [...] wiped the scutter that ran down the back of my leg with the grease-proof paper.

In derivatives

scutters, the (n.)

(Irish) diarrhoea.

1977		W. Burrowes Riordans 70: Who else could tell Father Sheehy that the baby had the scutters.
2001		G. Coughlan Everyday Eng. and Sl. 🌐 Scutters/Squitters (n): diarrhoea.

In phrases

tail-scutter (n.)

(Irish) a fart.

1966

P. Boyle At Night All Cats Are Grey 82: All the time keeping up the eternal litany of belches and tail-scutters that helped to make people keep their distance.