This won't be a permanent feature, I'm just taking a look at this episode from October since I'm watching it.
This show is sort of a learning deal, the AKB members are set tasks to learn things, though this week, which apparently was the last week before some changes, was a special featuring 'Sempai Idol 48', a group of older idols, both male and female brought together for this episode, and had for the first section the girls learning some interesting facts about there sempai, such as what they're doing now, and one male Idol apparently once had a really big star holding his hand backstage at an event. The viewers don't find out who, but it's told to one of the MCs, who tells the other MCs as well as Takamina, causing it to spread like wildfire through the 48 members present (including two NMB members). Some notable inclusions in the Sempai Idols is an older women who was apparently in the same niche as SDN, I know this cause I saw a year old episode of a show which had her, Takamina and some of SDN as guests, and the SDN girls were demonstrating their 'sexy skills' (I don't remember what it was called) and she demonstrated it as well. If your interested it can be found pretty easily by searching SDN, I think it's in the similar videos list for the only GAGAGA PV I found on youtube. It also features some of the girls who would be best called AKB's sempai, members of Onyanko Club.
Half way in we get sets of the girls performing some of the sempai's songs in appropiate dress, starting with Takamina, Ami, Yui, Mochikura and Myao as a boy band, followed by Sashii and Kitarie performing 'Pink Lady UFO' (or is it as) from 1977. Mayu, Lemon and Miyu (I think) are next with a song from 81, Miichan and the 2 NMB girls then perform one from 76 by the Candies. With most of the AKB girls behind them as backing vocals, Yukirin, Nyan Nyan, Akicha, and Chiyuu join a number of their true sempai in their first single, Seifuku o Nugasanai de. Acchan performs a solo number from 1980, before we head into a Sashihara led rendition of Heavy Rotation (never heard of this one) by all the AKB members who took part in the tribute acts, followed by Ponytail to Shushu.
For the second half we have group I think is made of crossdressers and transexuals, but some of them don't seem to be so I guess it's more than that. One of the crossdressers is as an AKB member, calling 'herself' COCO. Three of the transexuals are brought out, and Acchan, Sasshi and Harunyan get to touch one of theirs butt, before each getting to touch the same girls bust. I'm guessing they're freaked out by how real it feels. The second one actually exposes her breast. I'm sure not all of the girls in that studio were 16. We don't see much though, a nice heart blocks it from view. They then move on to the third girl, who more surreptitiously shows only those three her breast. There's also something with her cheeks, and they tough her butt as well. After revealing who's surgery cost the most, we're shown thse three as they were as men. Silicon breasts are brough in and the AKB girls take a look at them. Turns out the most expensive surgery was done to make her look a lot like Angelina Jolie. After revealing that her change cost not a single yen, COCO is brought to sit with the AKB members. Unfortuantely there was the oversight of putting her next to Yui, ensuring she'll be totally ignored. I kid. After that we get some pictures of members which I guess are meant to be them without make-up (they look exactly the same). One gues, Kaba points out how Takaminas pose it too manly. A bit later we have COCO and one AKB girl I don't recognise swapped.
This was interesting, though I homestly preferred the first half seeing AKB with their sempai, and I think the Onyakon Club team up deserves a mention.