During sex...does breast size matter a ton?

It really doesn't do much in sex. Yes they are nice, but it's not a super-important part of sex.
And no it doesn't turn me off at all.

Everybody has different boobs, they don't even come in pairs. One is always a bit larger. If a guy is interested enough in you to want your shirt off, he is happy with your boobs. :) I have known girls with big boobs, they mostly don't like them. They hurt your back, people roll over on them in their sleep, bra straps cut into you. And as someone already mentioned, many off us prefer small boobs, although to me it is like 50 french fries or 52, It don't really matter much.

To guys (like me) breasts are optional equipment. They're kind like fancy headlights on a car. I happen to like my girls with a nice, comfortable back seat, and a lot of junk in her trunk, if you know what I mean.

My wife has a nice swing on her back porch, and that's what men like me find hot.

I think it does not matter what size she is. I like to look at different size breasts and nipples etc. I get turned on by all sizes shapes and color.

Every guy is different, some actually prefer small breasts.

It wouldn't totally turn me off, but If I have her shirt off she's ready to go, I'm good to go. Granted, I can't give her a pearl necklace, but that's ok. There's other places on her body I can decorate with my "stuff." But don't get me wrong, big boobs are always good.

Well for me it's far beyond breast. It depends if man likes breast or a great Butt. as for me... I could take a woman just as she is as long as she could have a seductive attitude. who cares about breast. that's my opinion.