You are reading the manga hentai: Vicious Luck Full genre adult, Seinen, Slice of Life.
Introduce Vicious Luck:
Many people fantasize about switching partners and embarking on wild amorous adventures, but sometimes it’s easier said than done! Ju-yeong and Mina are in a somewhat “happy” relationship, but things are just bland… until a magic dice comes into play! The dice’s power changes the couple’s chemistry together and adds zest to their love life. Just one toss and a whole new Mina emerges! Maybe those fantasies can be fulfilled after all…