Six short lines carry a surprising amount of puzzling, playful thought. The speaker sets out to fetch a friend, and in doing so notices a reed that seems to be "reckoning the profits of drink," as if the plant were an accountant weighing up what a drink is worth. A reed grows by water and draws it up, so the image of a drinking reed is both odd and natural.
The poem then turns inward with a question: "How much to expect of vice?" The speaker seems to be weighing pleasure against its cost. The last two lines land with a rueful note. Desire, which should feel warm and spontaneous, has been "quite spoiled by reason." Too much calculation has drained the appeal.
The mood is wry and a little wistful. Sound plays a part too: "send to sea," "see a reed," and "reckoning" echo each other, giving the lines a light, slipping rhythm. Judging by the imagery, the poem suggests that overthinking can take the fun out of wanting something.