Between my Arms

This week is also coming to an end, and I still haven't started studying for my exams. Last night instead of studying, I ended up reading a light novel. Why am I like this?

I was walking with Tsūmen back to our class from the cafeteria. He was drinking some soda that he got from the vending machine. I was shaking the bottle of choco milk because the chocolate coagulates at the bottom of the bottle otherwise.

We were walking past the staircase near our classroom when I noticed Yasurouka and Gaisen climbing up the stairs while talking with each other. 

It was weird that Kizhashi wasn't with them. I rarely see Yasurouka and Gaisen together without her. Gaisen looked at me and smiled, while Yasurouka looked at me and sighed. What was this difference in reaction?

Tsūmen called out to him as both of them walked up and stood in front of us. "Yo, Gaisen-kun, and Yasu-san."