Ryuu Ou-sama no Okiniiri!

His nickname is “Snake Man.”
Because of his unattractive face, Riku has endured harsh treatment from his family and a lonely life without friends. One day, while at school with his younger brother, he is suddenly summoned to another world... What awaits him in this unfamiliar place is the overwhelming adoration of a stunningly handsome Dragon King! Chosen as the king’s “favorite,” Riku is even commanded to share the bed...!?

(Source: Libre, translated)

Note: Includes three extra chapters.