Touken Ranbu dj - Tsuru no Nakigoe wo Kikitai?

Pairing: Mikazuki x Tsurumaru

From Silver Lining:

Although Mikazuki and Tsurumaru have been lovers for a while, Mikazuki has never heard Tsurumaru moan. And he begins to think that it's because Tsurumaru doesn't feel the same way about him.