Deai no Waltz

The protagonist meets Irie, a bokkko (a bokko girl) who is also a student in the seminar at an arcade. He was having a heated game with her with high tension, which he usually doesn't see, but he misses the last train as it is. They decide to go to a love hotel and have sex in the flow.

(Source: Mujin Comics, translated)

Note: Published in Comic Tsuyahime Vol. 001