共喰い literally means "devouring one another" or "cannibalism," combining 共 (together) and 喰い (eating). It is an unusual, vivid expression that makes the song’s relationship feel dangerously intimate, as the lovers consume each other emotionally while sharing a "共喰いの paradise," or "paradise of mutual devouring."
"Love = Ego" is the whole thesis of this Travis Japan track, and the song keeps hammering it like a math formula. It opens with a question, "こんなに愛してもいいの?" (is it okay to love this much?), and then answers itself with a shrug: "どんなに愛したっていいよ / でも所詮エゴ" (love as much as you want / but in the end it's just ego). Even the hook spells out the ingredients: pride, vanity and desire.
The verses are pure night-city drama. The moonlight is murky, glass shards scattered across town are drawn to each other, and the lovers are "楽園で踊る共犯者" (accomplices dancing in paradise). One very modern detail: "伏せたスマホ眠らせ" (putting the phone face-down and letting it sleep) before they love each other. The paradise even gets a dark name, "共喰いの paradise" (a paradise of eating each other alive), which is a bit much in the best way.
Learner tip: 共喰い (tomogui) literally means cannibalism, here used for two people consuming each other. And "今日限りの永遠" (an eternity that lasts only today) is a lovely contradiction to remember: 限り means "limited to".
The bridge flips into stubborn independence: "あなたはあなた / つまり 私は私" (you are you / so I am me), whatever name you give the relationship. The ending is a show with no encore, "アンコールのない happy end" (a happy end with no encore), and a cheeky "ごめんね これが現実" (sorry, this is reality).