Can't Help Farting During Anal Sex?

I'm a gay male, recently began having anal sex. I usually bottom (even though I hate it; I would much prefer to top/alternate) but anyways it is very uncomfortable for me because when anything goes up my bum, fingers, cocks, it really makes me want to fart. I have tried fasting all day when having intercourse that night (I also used the washroom well in advance) so there was nothing in my system -- but I still felt like I had to fart. It is a very uncomfortable feeling. One time my partner pulled out pretty slowly and I accidentally, uncontrollably let a huge fart rip. It was so, so embaressing :( Last time it got to the point where I was so concerned that I might crap during sex that we had to stop. I have no discussed these problems with my partner (who is very loving and understanding) because I am embaressed, and he already has a way higher sex drive them me so I feel bad. Could it have anything to do with the fact that he has a very large penis? Someone please help me, thank you in advance! :) I will pick a best answer.