Here you all go. :) This idea originated from  metalzaki, but I threw in my own take.

This is from deviantART:

Peach's insanity was of much concern for her captors, so the Magikoopas had to think long and hard about what to do with her in order for her to be more docile and complacent. The problem took a while to figure out, but one decided that Peach's attitude could be augmented if she was controlled via sedatives. So, they whipped up a sleeping gas tank and a rubber oral mask for her to wear.

Once she wore it, however, things started to get even weirder. Instead of getting sleepy, she got more restless and continued laughing, even as she breathed in the gas. Since she had to be freed from the wall for the mask to be put on and the tank to be strapped, she appears to be more dangerous... though the door is once again locked, so she ain't going anywhere.

So, hope you enjoy this.