First time cumming while fucked

When I was young, my girlfriend's older black brother blackmailed me after he caught us having sex. I was made to suck his cock on a regular basis, sometimes while my girlfriend watched. One day he pushed me off his cock, made me turn over with my ass in the air. He poured canola oil on my ass and pushed his teen cock in my ass. It hurt at first, but after a while I started rocking back on it and my head got cloudy and the room began to spin. My body shuddered and my ass clamped down on his cock. Cum began to erupt from my limp little dick and I even cried out his name and asked him to fuck me deeper and harder. He thrust deeper in and all you could hear was balls slapping on my ass and me begging him to cum. Then he screamed out "fuck!" and unloaded in my ass, so much it was squirting out the sides. He asked if I loved him and I said "yes sir" with tears running down my face. He pulled out, zipped up and said, "good, think of me when you fuck my sister." I always did after that. He never did anything again, although I wish he did. Every time I ran into him, he just winked at me.