The Omake for episode 3 is styled as a promotional video for Fuka Academy. It's introduced by Mashiro, and shows various scenes of the idyllic life and academic opportunities at the school... and the occasional monster or fiery explosion, which quickly turn to static (as if they just realized they shouldn't be showing people that).
When Natsuki is forced to Show Some Leg to flag down a passing car, and the passengers turn out to be people they know. Reito can barely suppress his laughter, and Shizuru notes that it's "worth it" to see Natsuki like that. Shizuru's reaction either becomes rip-roaringly hilarious or heart-wrenchingly sad when watching it after knowing what happens in her Psycho Lesbian phase.
The part in Yukariko's special when she fantasizes about men.
Yukariko: Sometimes, I think about it too, if I was brought up in an ordinary environment and met a boy m-my age just like all girls do and fell in love and was held in his arms and OHHHHHHH! (pause) Oh-oh my! What am I doing? Oh, Lord, please forgive me for having such a lewd and vulgar imagination!
Haruka's Lotus-Eater Machine dream, which shows what the world would be like if everything went her way. She holds multiple positions of great power and influence and has an entire harem of naked women in her bath, which potentially says much about her true sexuality.