Meng Weiji Yi Qiannian

Lan Xieyi, an ordinary boy, wakes up one day to find he's travelled through dimensions and has become a demon's male pet! And he's even being used by the owner of this body to act as Bai Yueguang's substitute - this demon slave's body is actually quite sweet!

He must deal with the owner of the body, the Dragon Prince, Di Jiang; the cold heavenly immortal, Liu Yun; the wolf in sheep's clothing, You Chang; and the beautiful phoenix Bi Wu.

Their love makes Xieyi hesitate - if this is a dream, then when will he wake up? Where does this nostalgia in his heart come from? After transmigrating to a new world, the male pet strikes back and creates his own harem of beautiful men!

(Source: Kuaikan, translated)