The main character, Onii-chan, is a salaryman who has no choice but to work for a black company.

One day, his spoiled twin sisters, Yumi and Yuma, ask for an allowance and he involuntarily lectures them saying, "Those who do not work, do not eat."

However, his sisters interpreted this conveniently and started secretly planning to squeeze money and semen out of their older brother in exchange for lewd services. What will be the fate of his wallet and balls?!

[From official site]