The poem begins with a joke-like list of everything civilization forbids: eating raw mice, clawing enemies, mating or relieving yourself in the street. Then it turns to a dog who catches a wild scent and, after a moment of thought, squats to leave her own mark. The speaker watches this with a kind of quiet kinship.
Then it happens to her. Walking a mossy path through cedars and young pines, she feels a sudden urge to pee. The poem treats this as something close to a spiritual moment, "a seizure by immediate beauty." The place is so lovely that she answers it the only way her body knows how.
The tone starts wry and a little playful, then becomes warm and almost reverent. The last two lines are plain and bold, like a child's or an animal's claim. The speaker doesn't feel embarrassed. She feels, for a moment, fully part of the woods.