CLAM BISCUIT Share definition Flag A clam biscuit is pipe or a bong bowl filled with marijuana that has been burned down to its last hit. Hey John, dump out that clam biscuit and load a fresh one! CLAM BISCUIT by Nick Tindall April 25, 2006 0 0 Get merch Get the CLAM BISCUIT mug. Buy Now — $32.95 See more merch