The speaker plays with time, treating seconds as something that can be slowed, sped up, and even entered. By counting them, they seem to change speed, and the speaker decides to settle between them, in the small gaps where a person can simply exist as a wish.
From there the poem widens. The speaker wishes themselves into that space, then wishes other people there too: "her, and him, and her again." Everyone becomes a wish, and those wishes take the shape of smiles, wrinkled skin, freckled or pale or mahogany faces, and eyes in every colour. The imagery is warm and physical, as if hope shows up in the lines of a face.
The mood is tender, hopeful, and quietly joyful. What matters most is not whether the wishes come true. The speaker says "we sparkle being them" either way. By the end, the seconds are no longer something to chase or measure. They are simply "here with me."