Hatsujou 5-byoumae! Ponkotsu Around 30 Airu-san ga α no Ouji ni Aoraretemasu

One day, our protagonist is assigned to be a mentor to the president's son, Taiga Narukami, an elite boy with a shiny new look. However, Taiga becomes frustrated with Airu's uncompromising attitude, and finally takes her lips in a forceful manner. Airu's body gets wet under Taiga's rough kisses and fingertips. When Narukami-kun touches her, her body becomes so numb that she can't think about anything else...!

(Source: Brite Shuppan, translated)