I didnt fart !

Me and my boyfriend had sex the other night and we were doing doggy style and all of sudden we here like fart sound, he stopped then we went back at it again then it happend again i started laughing bc in my head i was like "wtf" and embaressed... Then he asked me if i farted of course i said no and he then said "you probably queef" i googled it and then i relize i did .. I was just wondering how do i not queef while doing doggy ? & why do i ?