Well, I don't know if it is considered a "monster", but my boyfriend is black, and his cock is a thick 8.5 or 9 inches. He isn't as huge as some of the black guys you see in porn, but he's bigger than alot of them, and bigger than most white guys you see in porn.
He was actually the first guy I ever had sex with, and for the first 7 or 8 months we were together, I only topped (even though he is normally a top). I love to suck him, although even now I have trouble deep throating him (mostly because his dick is curved, so the angle has to be just right). Eventually I agreed to try bottoming for him. He spent a lot of time loosening me up with dildos (starting with a small one and working up to larger ones) before he tried entering me. It was kind of uncomfortable the first couple of times that he did it… but eventually I learned to relax enough to enjoy it (and now I love it). Once I learned to enjoy having him fuck me, we kind of reversed roles, and now I am almost always bottom. He's been fucking me regularly for a little over 2 years now, and I have to say that because of him, my attractions have definately moved towards black men.
On a side note, we have a "friend with benefits" who occasionally joins us. This friend is white, with about a 5.5 inch dick. After being used to my boyfriend's larger cock, being fucked with the smaller one is kind of... anti-climactic.
Todd