When I took my boys to be done, I had to stay with each of them to hold their heads whilst OH stayed by the car holding them before and after.
It was not a pleasant experience, especially as the vet plonked the offending articles on the floor by the boys and asked us if we wanted to take them home. Do they fry up nicely with onions by any chance? My advice, if you do have to hold them, look away!!!
However, I was amazed how quickly they got over the experience, they were back to normal after a couple of days.