The twist in this poem comes quietly: the speaker isn't a person at all, but a pair of dancing shoes. Judging by the imagery, "slips me on," "her lively feet inside me" and the "huge white bag" filled with her clothes, the shoes belong to a dancer who wears them for hours of daily practice and for performances in front of crowds.
The shoes speak like a devoted, possessive lover. They treasure her touch and dread being left in the bag when she goes to school. They resent her male partner, who lifts and holds her and helps her up when she falls, something the shoes can only watch. The refrain "Hour by hour, day by day" captures both the closeness of practice and the ache of waiting.
The mood is tender but tense. It starts out warm and magical, then slides into jealousy, insecurity and longing, ending with the speaker insisting, "I'm the one she should be with."