Mana-mi is introduced to her sister Anzu's best friend, Aoi. One day, while her sister's back is turned in the kitchen, Aoi gropes Mana-mi's breasts and launches a tongue kiss attack. After staying over at her house, she immediately sneaks into Mana-mi's room, wets her nipples with saliva until her tank top is damp, and licks her sweaty crotch. The two of them make love through mutual hand jobs until dawn. From that day forward, they secretly, sometimes boldly, cover each other's young skin in love juices with cunnilingus and pussy play, all while trying not to get caught by her sister.
