At first it started out with difficultly finding information about
Pinkish (or Pinkisshu). An hour or so of researching later, and there is a LOT more to the group than I originally thought. They are the second to sing in the 5th video of TIF, following after Idoling!!! They only get around 27 seconds of spotlight, but it's something!

The quest for info! I like to dig up background on these groups, because it's interesting and fun. Though it's also sometimes quiet a chore if the group isn't well known. Over the last few days I've spent some time listening to Pinkish and trying to find out more about them. I first tried looking for videos on YT, and turned up with around 5 to 6!
The next step would be using search sites (I'm such a Google gal), but the problem is that with a name like Pinkish -lacking kanji or even romaji- I got a lot of results about things pinkish colored, makeup, etc. Totally unrelated to the Japanese idol unit. So then I used my thinking cap, and googled for 'google.jp' ~ since whenever you see that little 'jp' in a URL you know it's a Japanese site.
And TADA, I clicked on the link it turned up and from there I again searched Pinkish. The websites results were a little confusing for me, so I switched to images and was quite successful! Especially on one blog in particular; www.ecity.ne.jp ~ I'm not exactly sure who writes it, though I think it covers going-ons in the Saitama Prefecture.
The blog is linked to the YT account
Saijiman; which is pretty much the only place I could find Pinkish's videos.
Here are all of the entries under the label Pinkisshu. There are a lot of good pictures of the girls at different events, mainly from 2009. At the TIF only three girls performed, thus I first thought it a trio unit. But after finding their
ja.wikipedia page, I learned differently.