In olden days, when lucky dogs use to be fed on dead animal bones, their craps use to be white in colour. In some cases, they were semi-round and hence the name.
Oh crap, I've just stood on some dogs eggs.
a steaming pile of turd. a nest of fire snakes
excuse me m'aam could you tell me where i can find the nearest public convienience so that i can lay a nest of dogs eggs