Anal sex

I want to tell u about something i felt while anal sex in the last few weeks.
I don't really like anal sex (recieving) but if i m really horny i can't stand and sit on a cock . Last week, i made a group sex with a t-girl and a boy. First T-girl wanted to fuck me and i let her to fuck, everytime it hurts when first push so i dont like anal sex. After that the boy said i want to fuck too. But his dick was too big for me. But i let him to fuck me bec my ass was relaxed by the T-girl.

I sat on him and start up and down, after 2 or 3 min. i felt a pleasure and orgasm feelings. i feel like something blow in me . i felt really fucking pleasure that i have never feel. and my cock blowed without touching or masturbate, i didn't touch it . i feel the prostate orgasm or pleasure.
That was really good and interesting experience for me.
Is there anyone experience like that ???