My girlfriend's parents were away today, and she invited me to go home to sleep overnight. Imagining sleeping with my girlfriend, the two of us fucking each other that night made me feel radiant inside. Unable to take it anymore, the two of us immediately did "one round" first. I wanted to be fucked naked and cum in my girlfriend's pussy, but she insisted on not giving it. There was no other way, I had to put on a condom and fuck her.I was enthusiastic when suddenly my girlfriend's sister came in, saw that we were fucking each other, she quickly apologized and went out. Then today the appointment was suddenly canceled, so she came back. Ms. Non is an extremely beautiful girl, especially her big breasts make any man unable to take his eyes off. After talking for a while, my girlfriend went to take a shower, Ms. Non immediately approached, pressed her breasts against me. "You can ejaculate into your uterus." I couldn't resist her invitation, every time my girlfriend was absent, my sister and I immediately clung to each other, constantly releasing sperm into her uterus, until... My girlfriend suddenly came home early and found out everything...