expression, noun
Jocular, colloquial phrase used to express that something is easy or that one is completely at ease. Often said with a light, playful tone.
「試験、大丈夫？」「余裕のよっちゃんだよ！」
"Are you okay for the exam?" "No problem at all!"
彼はいつも余裕のよっちゃんって感じで、緊張しない。
He's always so relaxed, like it's a piece of cake, and never gets nervous.