BIZUI ELONG WO BU XIANG ZAI GEN NI DAI HAIZI LE

The dragon slayer Leon was defeated and captured by the Silver Dragon Queen. With his life on the line, he tried to use forbidden magic to curse the dragon queen, but the curse had unexpected side effects, and the queen lost control as they had a one-night stand.
He thought that the shame she would carry for the rest of her life would be enough to fulfill his life's purpose as a dragon slayer.
But two years later, when Leon opened his eyes, he found a young dragon girl with a tail sleeping next to him…