I don't care about size, i had guys with smaller cocks and bigger cocks. It's not about the size, since a woman has limited space inside, some can't take giant dick other might can. I had no bad experiances, the few guys with realy big ones knew to be more carefull.
Favourite position to blow, i guess you read my profile and saw that I got a thing for it

most favourite is on my knees with the guy standing, but it's not the most comfortable for the guy. Since I like to take time and not rush it, i prefer if the guy can be comfortable, so sitting on laying is more often the not better.