A red-hair witch impulse-purchases a boy and takes the boy home only to find out that she bought more than what she bargained for. Scanlation: http://www.surasplace.com/index.php/calling/67-webtoon/calling/1505-calling-11.html
The main character is a trap, whose sole purpose is to convert others into trap by whatever means possible. He seeks boys with feminine features or behaviors and through very comedy based tactics convinces them to embrace the trap life style.
From Yaoi Shake Scans: It's a story about the student Sunose Kei, who fell in love with the handsome yet cold teacher Yukimura Tsukasa, who looked annoyed everytime his student visited him. Even though Yukimura-sensei can't turn away from Kei, he spends the night with another man. And what's more is that he spends it with his ex-lover?! Now that’s a student-teacher story that you can't miss.