This to stop her from producing spider silk, I assume?

I'd guess that it's to force her to produce "spider silk" as that looks suspiciously like an enema bulb.

I don't get it.
What is going on?

Nadux said:
I don't get it.
What is going on?

Like anything with Gaoo, commentary may be needed for context.

アイドルってう○こしないんだよね？
多分、浣腸とかしても、う○こしないはずだよね。だってアイドルだし・・・。ヤマメちゃんが本当にアイドルかどうか確かめてみよう。わくわく。ぷすっとな。

I'm afraid that it might actually be that thing with shoving a mint up your butt again...I hope not.

Translated commentary:

Idols don't poop, right?
I think she probably won't even poop if I give her an enema, right? She's an idol after all... Let's try to find out, if Yamame-chan is really an idol. I'm so excited. *poke*