Nikky's poem is a short, brutal image of emotional harm. The speaker describes someone biting into her heart, which reads less as a literal attack than as a picture of being used and hurt by another person. The attacker looks her in the eye while he does it, grinning, and the speaker notices something empty in him, as if he is "missing something inside." That gap suggests he lacks empathy or feeling of his own.
The cruelest moment comes when he wipes his mouth and calls the act "refreshing." He treats her pain like a cold drink, something he took for his own pleasure and thinks nothing of. The title, with its cheerful word in quotation marks, sharpens that contrast.
The speaker's reaction is quiet and helpless. She just lies there and cries, with no fight and no reply. The mood is bleak, cold, and unsettling, and the plain, simple language makes the cruelty feel even more matter-of-fact.