Jishou Kanojo no Kouhai ga Iiyottekuru.  

The Story of a Kouhai Who Flirts with Me as a Self-Proclaimed Girlfriend, 自称彼女の後輩が言い寄ってくる。, Jishou Kanojo no Kouhai ga Iiyottekuru Hanashi

A 5-part one-shot about a beautiful girl flirting with her self-proclaimed boyfriend.