I distinctly recall a dinner scene where, after eating, everyone kind of hung out chatting for a bit, then used dedicated bowls to discretely hork up the undige

I distinctly recall a dinner scene where, after eating, everyone kind of hung out chatting for a bit, then used dedicated bowls to discretely hork up the undigested remnants. I seem to recall something about "zippers" at a cellular level? It's been a while and my copy is long gone.