does size matter

OMG, that's beautiful!

6 is good for oral, but I like big toys, so the bigger the better for my butt.(15 max)

A nice size is good.
It depends on what you are looking for and like.

I think that size does matter. I want to suck a cock that I have to work at getting it all in my mouth, so around 7" and thick. As for getting fucked, I want long and thick. I want to feel the stretch of a thick cock and I want to feel multiple inches sliding in and out of me.

for some people it matter so much!

I will admit it. I like to get fucked by a big cock . . . 8"+ and I love to see my wife take it as well. The biggest that I have had was 9.5" and thick and it felt great! Yes sucking a cock that big is a challenge, but getting my ass filled up . . . another story altogether! LOL! That's not to say that I will not take smaller, but bigger is always my preference!

From my experience it matters to some but for a wide variety of reasons , myself I am right around 7in. When flaccid uncut and we'll over 11in. When erect I have always been on the large size which when young can be treated as freakish . In fact even with adults it can be treated as more of a novelty some can really love it where some can be hesitant or intimidated. The larger size can be a real pain at times like when getting in and out of vehicles or riding motorcycles which I do .
Personally whether small , average , or large it should be all about the pleasure people can and should have .

Never met a cock I didn't like. Love swallowing a small cock whole and love the heft and weight of a big meaty cock in my hands and the novelty of having something that big in my mouth. When it comes to anal, I don't want a cock with a monster girth.

Yes. Size does matter. I just want to be filled up. The smaller guys I have been with made up for it by giving me unusually large loads.