noun
long unbroken stool; sausage-shaped poop
Colloquial term for a long, solid piece of feces that comes out in one continuous piece without breaking. Used in casual, often humorous contexts.
今朝は一本糞が出てすっきりした。
This morning I passed a long unbroken stool and felt great.
子供が「一本グソが出た！」と嬉しそうに報告してきた。
My kid happily reported, 'I did a sausage-shaped poop!'
Compound of 一本 (いっぽん, 'one long thing') and 糞 (くそ, 'feces'), literally 'one long poop'. The reading ぐそ is a voiced variant of くそ in compounds.