Gobaegui Jeongseok

Hui-Jae, who is always unlucky, is suddenly kicked out of his room, gets fired from his part-time job, and is also dumped by his lover. Finally, Hui-Jae decides to go on a package tour with the hope of starting anew and avoiding misfortune.

After arriving in Paris, he is desperate for a partner who doesn't come even after waiting for three hours. Just as he thinks nothing is going to happen, Seon-U, a college classmate, comes to Hui-Jae's hotel room to tell him about the rumors about Hui-Jae's ex, Yu-Jae.

In fact, Hui-Jae and Seon-U were classmates in middle and high school. Hui-Jae confessed to Seon-U in high school, but after Seon-U turned him down, they became distant. When Seon-U brings the past up again, Hui-Jae takes off Seon-U's pants and starts licking his genitals...

(Source: BOMTOON, translated)