Any small spherical fecal bolus within the rectum left after a premature contraction of the external sphincter. In general, this refers to a bolus that is too small to exert sufficient intrarectal pressure to trigger its own evacuation but large enough to be perceived by the individual. Upon subsequent rectal packing, and because they have become necrotic with age, these tend to form a black cap, much like a stocking hat, at the leading end of the next stool.
Bryan, I had to cut-off off that last shit early because I was going to be late for tennis practice. I didnât get it all out and hence, a large tim pool will be first out tomorrow morning, black-capping my morningâs turd. I canât wait to see it.