The poem is very short and deliberately puzzling, but its mood is easy to catch: someone feels out of place among people who aren't kind to them. The speaker is at a debate night, surrounded by "unkind friends," and the only edge they have is "one lie," a single bluff or bit of cunning. They compare it to a rat in a warren, a small, hunted creature that survives by knowing its hiding places and its one trick.
Then the poem turns sharply. The speaker says they give the best advice in bed, and the final line, "mustering the river," is odd and open. It might suggest gathering strength or calm, or imagining something large and flowing to escape the tension. We can't be sure.
What comes through is a mix of defensiveness, dark humor, and private longing. The speaker seems sharp in public only through trickery, but more honest, perhaps more at ease, in intimate settings. The mood is wary, wry, and a little lonely.