I Want Siblings (うらおん!きょうだいほしい Kyōdai Hoshii), is a Ura-On!! special 2 minutes and 40 seconds long.
Number 1: Mio & Mugi
Looking at Ritsu and Yui having younger sibling had made Mio sort of jealous. Mugi thinks that if Mio had a sibling, it would be a dependable older brother and everyone thinks that it would be a perfect match. Everyone thinks that if Mugi had a sibling, it would be perfect for her to have an older sister that was classy (according to Ritsu).
Number 2: Yui
Ritsu wonders how Yui would be if she had an older brother. Yui liked the idea and thinks that she should have a twin brother, exactly like her. Mio thinks that it would be quite a troublesome for Ui to handle the two of them (since Yui and his brother would act like little kids). Yui also suggested for Ui to have a twin sister.
Number 3: AzuSawako
Yui think that it would be cute for Azusa to have a quintuplet twins. Ms. Sawako then wondered what the girls are talking about and Azusa explained everything. Ritsu thinks that if Ms. Sawako had a sibling, it would be an unruly older brother (which later Ritsu pictured as an old man and Sawako was mad, thinking that she is not 'that' old enough).
- Youtube (I Want Sibling)