Shooting My Star☆ ~Onii-chan, Kakugo Shitete yo ne♪~

On a day when Subaru was striving toward his dreams, his parents suddenly announced they were going on a two-week overseas trip to celebrate their silver wedding anniversary. The news left Subaru and his younger sisters, Haruka and Towa, stunned.
Worried about protecting his twin sisters during their parents’ absence, Subaru tried to stay vigilant. But the two little devils had their own plans brewing…
After a chaotic first day, Subaru collapsed into bed, muttering, “Two weeks of this…” and quickly fell asleep. Little did he know, two shadows were creeping toward his bed.
When Subaru woke up to an oddly warm sensation, he found his sisters, completely naked, fighting over who got to touch him first! Ignoring his protests, they debated who would go first, pinning him down and taking turns…
Just when things couldn’t get crazier, their cousin, Nene Watanuki, showed up, claiming their parents had asked her to help out. With a new rival (?) in the mix, Haruka and Towa became even more aggressive in their advances. And when their childhood friend, Nagi Yomohiro, got involved, a four-way battle of love and desire began!

[Translated from dlsite]