"Fling" seems to be about casual, half-committed love and how quickly the days that surround it slide by. The opening lines are almost offhand: love "for company's sake," love "in the cakehouse." Both suggest something small and comfortable, more about not being alone than about deep passion. The cakehouse adds a sweet, slightly silly note, as if this romance is made of treats rather than substance.
Then the poem shifts. Something "carried them away" to a place "where Monday is / a little rope of life." The image is hard to pin down, but it hints at ordinary weekdays as a thin line we hang onto, easy to overlook. The final lines make the point sharper: most people don't notice this rope until "it is too late for any plea," when it can no longer be bargained over.
The speaker sounds quietly wistful rather than angry. The mood is light on the surface but touched with warning about wasting time on passing things.