underpants / sleepwear
also known as the "you should probably wear something more than just these things out in public unless you want to have a friendly discussion with your local law enforcement and end up on some list, somewhere" section. we say sleepwear, but we all know that nobody is sleeping at your slumber party anyways, I mean, you didn't buy new batteries for mall madness and order those zit stickers off ebay for nothing.