Green’s Dictionary of Slang

(Irish) to defecate.

1987		V. Caprani Vulgar Verse and Variations n.p.: And when I think of all that I did for him! The big fucker oughta be tied to a cow’s tail and scuttered to death! [BS].
1994		J. O’Connor Secret World of the Irish Male (1995) 86: They are laughin at the rest of us, they are scutterin themselves laughin.