Stairs, the ultimate source of evil. Even beat Darkside once. Also its cute that Rei-chan know when to drop the jokes and treat her Kei-chan with care.
The joke in the last panel is that Utsugi writes "Bishi" with her fingers, that's something like "beauty"; surely you sometime heard the word "bishoujo" or "bishonen" which means handsome boy or girl respectively, that is a combination between the words "bishin" and "shoujo" or "shonen". Well, at least that's what is written in hiragana.
The joke in the last panel is that Utsugi writes "Bishi" with her fingers, that's something like "beauty"; surely you sometime heard the word "bishoujo" or "bishonen" which means handsome boy or girl respectively, that is a combination between the words "bishin" and "shoujo" or "shonen". Well, at least that's what is written in hiragana.