Citations:piss clam

Noun: "(informal) a clam which squirts water, such as a geoduck or a long-neck clam"

 * 1998, Charles Simmons, Salt Water, Chronicle Books (1998), ISBN 9781452123561, 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 (2012), ISBN 9781468562316, 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 (2013), ISBN 9781429976350, 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.

Noun: "(slang, vulgar) the vulva"

 * 2001, William A. Kelly, My Father Was a Bootlegger, Xlibris (2001), ISBN 1401014844, page 83:
 * When I got far enough away she finally lifted her dress and showed her “piss clam” to everyone else.