How to Capture a Scheming Demon King

An Liu is a demon-taming mage. Demon-taming mages form contracts with creatures whose blood carries demonic power, then control and command them. Once a contract is made, both the mage and the contracted creature are branded with a magical contract mark. An Liu commands them through these marks. In return, he must provide his own magic power to sustain them. Magic power can only flow from the marked patterns of a contract brand, so the contracted creatures receive it by kissing and licking the marks on An Liu's body. As a demon-taming mage, An Liu has an inborn, overwhelming desire to possess powerful demons. One day, he encountered a mighty Demon King. The Demon King was cunning, and it took An Liu every bit of effort to make a contract with him. But this time, the contract mark was branded in the most intimate place on An Liu's body. So An Liu had no choice but to be pinned beneath the Demon King every day and supply him with magic power. The Demon King needed a great deal of it, and each session lasted a long time. Blushing bright red, An Liu asked him, "Are you done yet?" "Not yet, my dear master. I still haven't had enough," the Demon King coaxed him softly. Theme: Why not make a small sacrifice to achieve your goal?