My Little Stepsister Gave Me These Kissing Coupons A Long Time Ago And Today, I Keep On Using Them Every Day Vol.10 Lea Misaka

The older brother had always been weak and prone to catching colds. So when they were young, the younger sister gave him a kiss ticket as a birthday present. It was a wish that he would kiss her and pass on his illness so he would get better. The brother and sister grew up and became students, and one day the brother suddenly handed the kiss ticket to his sister...