I have done it three times with escorts only but not intentionally. The 3rd was very recently (25/12/15).
In each case it wasn't planned and in the 1st case I wasn't told and it was an outcall at the Hilton Birmingham. She made a real mess on the bed that I had to sort out! She claimed that she hadn't realised she had started.
2nd time was in Leeds a different SP, she announced it just as I was about to go down on her. I stuck my index finger into her quim but there was no blood so carried on with RO which she enjoyed, however, when I started piston pumping her fanny it was like a scene from a Quentin Tarantino film frikking blood all over the shop. After we calmed down she realised that she had some explaining to do to her brother whose house and room we were shagging in
A little pissed off though as there were no shower facilities so had to make to with toilet paper and wet wipes until I got back to the hotel I was staying in.
3rd time was similar to the 2nd occasion again a different SP but told quite late in the day although we hadn't actually started but I went with it any way and I got to shower before I left. Not too messy this time but messy enough