Drawn by sweet temptations and indulging in sex with my girlfriend's older sister, Suzuki Mayu GOUL-006

Taichi, a 20-year-old male college student, is dating Yui for the first time and wants her to help him lose his virginity. He's invited to her house, seeing this as an opportunity. He goes to her house thinking this is his chance, but unexpectedly finds himself with Mayu, an older sister even more beautiful and cute than Yui, with huge breasts. "Taichi, still a virgin? Since it's your first time, let me practice..." she murmurs.