User blog comment:Jopjopjop/Volume 18 Spoilers/@comment-82.242.251.205-20140627213712/@comment-98.93.219.106-20140628080011

To15sok: If I had to guess, it could be one of the following:

A) Issei and Vali have come to a mutual - if not true - understanding and have begun to bond as friends.

B) The two of them thought about relaxing the same way after an intense battle or training session.

C) Issei has begun to significantly influence Vali's way of thinking.

D) Vali has begun to think more like Issei to better understand him and simultaneously spite Rizveim. (Without Issei's influence)

Please bear in mind that this is my conjecture on the subject/question.