Mine was done thirty five years ago. I found that wrapping them up in cotton wool inside a tight pair of Y fronts (thirty years ago remember!) was a great psychological boost to lessen any discomfort.
Thinking about the poor little chaps resulted in the normal reaction and less than 24 hours after the snip, and to my wife's apprehension, I carried out a successful functional check.
Which is more than I will be doing tonight!