Ah, I see we need to define terms. For me, a big penis is more about girth than length. Yes, a really too-long shaft hits the cervix, and if it's too hard a slam, the pain can make you jump right out of bed.
My husband's cock is just a little too long, and when he would a long slow shove in as far as he could, then hold it, I came more than once as he held it. I have NO idea why. This worked with me lying flat on the bed facedown, or doggie style or missionary, but it was best with me flat on my stomach, arching my back so he can get in, then closing my legs, with his thighs lying on top of and aligned with my thighs. ANY movement would set me off, and him soon after, very little exertion possible, or needed.
When I think of a big penis, in my head I see a thick cock, which fills you so full it is exquisite. A thick cock reaches all the places which make me come hard, and each stroke pulls on the labia, which in turn pull on my clit.
I think you could say I'm an equal opportunity cock lover.