several things come into play for me. I love thick cock when I'm getting my little pussy slammed. I love the stretched to the max feeling. when I'm taking a cock in my mouth longer it's preferred ( easy on my jaw) but I want it jet black thickly veined, uncut and a heavy cummer. when I'm taking it in the ass too long or too thick can hurt if my lover is impatient.
It's really a combination of all.... But i must agree that the thickness and the way it makes me feel full has to be tops. But another thing with black men is, it seams that there driven to make sure it's the best sexual experiance of your life. I really can't explain it. It's hard toput into words what my mind goes through.