I have.
Happened about 3-4 years ago, back in my SD4M days.
Met a early 30s SB in my hotel. She was older and heavier, not so pretty as in her photos, but she was there. Represented herself as Eastern European, but I think she was really Middle Eastern - Arab? As she had a huge rack, and as I am not so familiar with the joys of playing with large mammaries,  I decided to go ahead anyway. Mistake!

Got to the bedroom and she asked me how long since I had sex. I said 2 months, which seemed to please her. Truth was, it was only the day before! - I can't remember if that was a day I did one or two SBs!  In any case,  I was already a bit drained, and would be long lasting. At that point she warned me that she was "OCD", and after a few  min chitchatting we got naked.  That was where things went south.  There was basically no foreplay before she had me lie on the bed, and she directly mounted me, cowgirl style. I think she was sex starved. She went straight at it,  and as time went by, she increasingly lost control and went into a sexual frenzy.  Never seen anything like it, she was riding me as if there was no tomorrow. She started off moaning and groaning and saying things in a foreign language - sounded like Arabic, or maybe Turkish? She got louder and louder as she got more and more frenzied. At this point I was telling her to be quiet, slow down, stop! She ignored me. From then on, she essentially raped me. She kept getting more energetic and faster, the more aroused she became, and shouted louder and louder.  I don't understand why security was not knocking on the door. I was of course erect, from the stimulation, but I was not enjoying it, which added to the fun the day before meant I lasted a long time.  Meanwhile, she was in a non-stop frenzy. I don't know how long she kept going like that, maybe 20 min, 30 min in total, but eventually she climaxed with a piercing scream, to let everyone know of her success!  I have never been so relieved in my life, my ordeal was over!  

But it wasn't over. As she finally stopped, and went to get off, we both noticed that the condom had come off! She had ridden me that vigorously. At that, she just flipped out. More screams, and she ran to the bathroom, where she remained for the next 20 min or so. I think she was douching herself. After that, we hardly said anything to each other, we get dressed, and she left. I was in bits. Basically, she raped me  - I wanted her to stop, and she ignored me.  I have been more sensitive to women claiming date rape ever since.  

The other take away lesson here though is for those of you who say they are happy to have their identity known. But what of contraception failures - what if she got pregnant? In my case, she did not know who I really was. But some of you would be easy to find, if child support was in prospect...