My girlfriend's older sister seduced me in provocative clothing! My rationality crumbled, and I ejaculated until my sperm flowed backwards. (Fujimori Riho, MIAA-813)

I was astonished by her sister's outfit! "Huh? Is that pajamas!?" Even though she was dressed, her breasts were completely exposed... everything that should normally be hidden was visible! I didn't know where to look! A transparent sailor uniform, athletic shorts, a swimsuit... and a reverse bunny girl outfit! If I were tempted like this, my rationality would crumble! I'm sorry to her girlfriend, but her sister always lets me have unprotected sex! I wonder when she'll find out about this relationship... But now I can't stop, too much sperm is flowing in!