Kurt loved to sing, especially with Blaine. Things he couldn't find words for, he found songs for. It was one of the reasons that he loved musicals. Songs were the emotion, and they made sense. There was nothing quite as romantic as their own song.
As much as Blaine liked the tone of his voice, Blaine's own was swoon worthy. Part of it was his classic charm, but people just gravitated to him. He also liked the blend of both of them in the chorus. Together they had a wonderful two part harmony.
EVERY MOMENT AS LONG AS YOU'RE MINE I'LL WAKE UP MY BODY AND MAKE UP FOR LOST TIME...