Ahh, Miss Matsugane, hands down one of my all time favorites...

I've seen her in tons of outfits(as have alot I'm sure, who follow her), and that one is a really good one, not the best, but really nice emphasis on her amazingly fleshed out rack!

To answer some questions about Yoko, her age is 22(maybe 23), and she's a Japanese H cup, roughly translating to an American D/DD.
Personally, I think she hasn't updated her size in awhile, she went through a growth spurt a couple years ago(anyone who's seen her Spiritual DVD and anything after that will attest to that), and she looks bigger than some girls who claim a bigger size. Rio Natsume is a J cup, but it looks hard to tell who's bigger to me.
Here's one of the more recent pics I've gotten of her...