OPPAI Life Prequel!

My student life is almost over...At that time, I had a dramatic reunion with my older sister Ayane, who had taken care of me since I was a child.Not only that, but Ayane also owns a giant OPPAI! Naoto-kun, do you like my OPPAI that much? It looks like you can just act as your lover and suck the huge OPPAI as much as you like! However, his childhood friend Chika comes rushing in! Chika is also a huge OPPAI! Chika's OPPAI is only for seniors! Ayane...Chika...my OPPAI life has begun! !