I vacated the grass runway to the left at a fair lick, and felt the tail begin to step out determinedly to the right, precursor to a groundloop to the left.
SSD,
I've done exactly the same thing on a couple of occasions over the years, when starting my turn to backtrack, at a little faster than normal speed, in the interests of a more efficient glider-towing operation.
After some fancy foot work and a shot of adrenaline, I was thinking "Er, let's not do THAT again!"