Gu Gu Ganmo: Episode 2 (EUF)

Gu Gu Ganmo is an incredibly obscure anime series for a young audience that features a pink bird and a bunch of kids doing a lot of raunchy and gross things to be funny. It was apparently too extreme to air outside of Japan so we never actually got an english or spanish dub at any point, I don't think there are even subtitles available for it.  

The only thing that we have right now are some small clips of comedic underwear exposure. This one being the very best one. Basically, what happens is that this female teacher is having trouble with the pet birds the kids have (a giant pink creature) and at one point she must rescue a kid and his bird from falling out of a window. The other kids decide to help her but they pull her pants off instead, revealing her white briefs with a Koala on them.

Classic pants fall down gag.

Tighty whities with cute prints on them. Anime's best gag.

Later on, a male teacher comes in and helps her but her pants keep falling down, something that happens numerous times, and the kids keep laughing at her embarrassing Koala panties, making her blush by being seen on them.

Its a great clip that really doesnt shy away from pulling her trousers down at every chance it gets. The animators must have had their fun. 

Full video: