Gwangyeyeokjeonbeoteun: Dodohan Geunyeoreul Gyoyukhaejuja

Hyunjoon, a retake student, explodes in inferiority complex after being tutored by his rival Nari. After pressing an unknown button that appeared in front of him, Nari begs Hyunjoon to give him sex education. The second short stories of the Relationship Reverse Button series!
(Source: TOPTOON, translated)