柄じゃない is a Japanese expression meaning that something is not suited to one's personality or usual image. It literally refers to something being outside one's "character" or "style."
In the song, the singer admits that wishing on a star is not like him, yet he cannot stop hoping because he ultimately wants no one but the person he loves. This understated phrase reveals his vulnerability in a memorable, conversational way.
This is a Christmas song sung by someone who keeps insisting he is above all the Christmas fuss, and then fails at it completely. Bells ring somewhere, words that are not like him pop into his head, and he catches himself wondering "なんで恋なんかしてんだろう" (why on earth am I in love?). He blames the endless holiday songs and the town that is "わざとらしく きらめく" (sparkling a bit too deliberately). Then he notices that how often he wants to see her, and how much it hurts when he can't, are telling him exactly how he feels. He already knows. Asking "サンタとやらに" (this Santa guy, or whoever) would be pointless anyway. The little とやら there is a nice word to learn: it adds a shrug, like saying "so-called".
The funniest part is his grumbling about couples wearing reindeer antlers: "よく人前で出来るなぁ" (how can they do that in public?), followed right away by "いや 羨ましくなんてないけど" (no, it's not like I'm jealous or anything). Nobody believes him. Underneath the sulking he is honest: he wants her beside him, wants her thinking only of him, and admits that even if she answered his confession with something other than what he hoped, he still "なれやしないから" (just couldn't bring himself to) stop liking her. Wishing on a star is "柄じゃない" (not my style), he says, while looking up at the sky anyway. Every time he gets close to saying too much, he decides it would be uncool and long-winded and just sums it up: "君が好きだ" (I love you). By the end he promises to say it "聞こえるまで何度だって" (as many times as it takes until you hear it), which is a lot less cool than he was trying to be, and much sweeter.
back number is a Japanese rock trio formed in Gunma Prefecture in 2004 by singer and guitarist Iyori Shimizu, with Kazuya Kojima on bass and Hisashi Kurihara on drums.
The band signed to Universal Sigma and made its major-label debut in April 2011 with the single "Hanabira".