Ano Ko to Ii Koto aka Anoko to iikoto is a two episode OVA released in 2015. Each episode is 19 minutes long. It takes it’s material froma manga.
Episode one is titled Konna Mune demo Aisaretai!! (These Breasts Want to be Loved, Too!). High school student Ookoshi discovers the secret of his well-endowed classmate, Takita—it turns out that Takita does not have the breasts that everyone around her believes her to have. Fearing that Ookoshi may expose her secret, Takita “gives” him something irresistible as an incentive.
Episode two is called Souda Imouto to Renshuu shiyou. (That’s Right! I’ll Practice with my Sister!) After arranging a meetup with a girl online and thinking that it may escalate into something lustful, Ami’s older brother decides to practice having sex with Ami. Of course, she is not willing to let her brother have his way with her, unless he completes a certain “challenge.”
The first episode of Anoko to iikoto adapts chapter 5 ( Konna Mune Demo Aisaretai!! ) which tells the story of a girl with small boobs who used pads to make her chest look bigger and her classmate who discovers her secret .
The second episode adapts chapter 6 (I Know, I’ll Practice with My Little Sister.) which tells the story of an elder brother who finally gets an offline date but being an inexperienced virgin has this “brilliant” idea to ask his sister for practice. Chapters are faithfully adapted.