Watched two scrapping on a lane yesterday, really going for it just like Robin's do. They were hanging on to each other for at least three minutes until I went to pick them up then they released and carried on over the hedge.
I used to get it regularly in my big toe. I was told to look at my diet and try to find the trigger foods, I found out it was fizzy orange lucazade and strawberrys. My mates was always set off by tomatoes.