Imouto to Sono Yuujin ga Ero Sugite Ore no Kokan ga Yabai

妹とその友人がエロすぎて俺の股間がヤバイ
Since his sister’s math grades are declining, his mother orders him to teach him how to study.
Her sister doesn’t want to be alone with the protagonist, so she decides to take care of her sister’s friends as well.
A friend with an aggressive personality fell in love with the main character from the beginning because she was good at teaching her studies her.

Her friend her touched her body her and her sister her accused her of being lazy.
When you suddenly notice, you’re in a state where you’re being pressed by both!?
A tsundere younger sister in the prime of puberty and a friend of a slightly gal-like busty younger sister.

which one would you choose?