http://www.nicovideo.jp/watch/sm3680432
紫「？」
藍「三歩さがって主の影踏まず♥」
まんまるおしりの後姿を見守りながら～♪

Yukari: "?"
Ran: "I'm walking three steps behind, so that I don't step on Master's shadow.♥"
...she says, while gazing unflinchingly at her Master's round backside~!♪