I'm not going to give an opinion one way or another on the truth or fiction of your story. I don't see any reason to flatly disbelieve it. For sure it's possible, for sure there are people who get off on doing that, gross though it may be for the rest of us. So I'll forge ahead on the assumption that it is the truth, n'kay?
Without some commentary from you, though, it's just bragging.
Did you enjoy it? Did she? Was it everything she hoped it would be? Would you do it again?
Fulfilling a sexual fantasy is fundamentally disappointing, because it can never live up to your mental picture. Discuss.