I Became A First-Class Guide Thanks To My Childhood Friends summary:

[The twin brothers love me too much. What should I do?] D-class guide Qiao Yang, because of a drunken accident, discovered that he could use the two A-class sentinels, his childhood friends Zheng Jia and Zheng Yan, to enhance his own class. In order to retain this rare S-class status, he chose to conceal his exploitation of them. However, during the repeated interaction with the two, he gradually becomes aware of their feelings towards him...