I don't know if such a thing exists, but I'm willing to say that it does - cos I think I just had one!
I was whacking away as usual, and I was coming close, and I heard footsteps, so was a little distracted. It was too late however and I came. I ejaculated along with an orgasm (albeit a not very powerful one). About 2 seconds later I noticed that I felt somewhat different, so I continued to whack away (without the usual extreme sensitivity that usually follows), and about 3 seconds later I came again, with another ejaculation, and a very powerful orgasm. There was a LOT of cum, and I lost my erection almost instantly after, but I was very satisfied!
Anyone else had this?