From Wiktionary, the free dictionary
piss clam (plural piss clams)
- (informal) A clam which squirts water, such as a geoduck (Panopea generosa) or a long-neck clam (Mya arenaria).
- Synonym: pisser
1998, Charles Simmons, Salt Water, Chronicle Books, published 1998, →ISBN, page 157:Some years we dug for piss clams. Small holes showed up here and there in the wet sand at low tide. When you stepped next to one a stream of water shot up your leg and you knew a steamer was underneath.
2012, Bob Vargovcik, Bayonne Boy, AuthorHouse, published 2012, →ISBN, page 14:When we saw a piss clam piss up through the mud, we would dig him up with the pitchfork.
2013, James Kirkwood, P.S. Your Cat Is Dead, St. Martin's Press, published 2013, →ISBN, page 142:Me, happy as a piss clam at high tide, workin' as a busboy in a deli afternoons and nights, other odd jobs during the day.