The speaker compares herself or himself to a cigarette and a former lover to the lighter and smoker, turning a relationship into a story about addiction. At first the attention feels thrilling: being "lit up" makes the speaker feel alive. But the same spark that excites also burns. The lover takes in a little more of the speaker with every breath, using them to relax and calm down, while the speaker slowly wears away.
The ending is the most painful part. Once the cigarette is finished, it's tossed aside, and the speaker is left as ashes in the rubble. The short, flat lines at the close, "I wasn't special. I wasn't unique," sound worn out and bitter. The speaker realizes they were only a habit, a way to escape, and never truly loved. The mood is sad and resigned, with a sting of hurt and self-doubt underneath.