Oha Star Morning Musume drama -
OMG. Aika is so cute. But do the other members think she's weiiirrd? 

!!! That was funny! Aika's super pretty in that, and I LOVE how they played the Darth Vader theme when Yossie walked in on Sayumi, Eri, and Ai talking.
Also, I think the deal with Aika's "hurting" during the chorus-- my guess is that she may be doing the humming to keep in time with dancing. It could be a little cue to help her out (and not as visible as mouthing 8 counts, which can sometimes be a tough habit to break for some new dancers) and get the dance, because she does sing out when she actually has to and doesn't hold back like that.