When Saaya hears that her childhood friend Mizuki has a boyfriend, she is surprised to learn that the person is a woman, but wishes Mizuki happiness. One day, Mizuki begs her to let her practice with him, saying, "I've never done anything sexual with another woman before, so I'd like you to let me practice." Saaya, who is weak to pressure, agrees to help him practice cunnilingus, saying, "Only if it's over my clothes..." However, Mizuki's cunnilingus...