The speaker is on the phone with someone they clearly care about, and the call leaves them frustrated rather than comforted. The telephone distorts the other person's voice, which the speaker remembers as "green," fresh and alive. Through the wire it comes out harsh and artificial, and the "vibrant plastic" seems to cry against the ear instead of carrying real warmth.
The second half turns into a wish. If only the "clay machine" did not have such a hold on them, the speaker would be face to face with the real mouth, close enough to feel breath. They imagine escaping into that breath, light and fragile "as dandelion." The mood is longing mixed with irritation at technology that connects people while keeping them apart. The date line, midnight, adds a quiet, lonely feeling, as if the call happened when the distance felt biggest. Short, abrupt lines make the speaker's disappointment feel immediate and a little raw.