"My dear, you are fully aware that my vocals are not the most preferable when it comes to singing, and yet you still persists?" He laughed ever so slightly, imploring him to sing along with you.

Your voice was melodious compared to Zhongli's — who's sense of pitch was lacking in terms of singing, thus preferring to listen to your voice than to himself.

Despite his great efforts of hiding it, you'll catch him humming your favourite song every once in a while.