KWSN said: ... is that alcohol, cause Sayaka looks drunk.
Calpis has its origins in the Central Asian drink Kumis ( http://en.wikipedia.org/wiki/Kumis ), and should have very low amounts--bute clearly present--amounts of alcohol.
It simply looks like Sayaka is just annoyed that Kyouko is trying to take a sip out of her drink instead of getting her own, while Mami's like, there's still more here.
