I was waiting to see if someone who actually had a C-section would respond first, but no takers.
I know in Mexican hospitals when a mother has a C-section, they stitch her up and then before taking her to recovery, they bind her stomach tightly with a wide Ace bandage-type of wrap. They also do this with a vaginal birth, but usually a few hours later (in my friends' experiences).
I would imagine you can do it whenever you feel comfortable doing it.
I tried binding at about 24 hours post vaginal birth and ended up cutting the bandage off with scissors an hour or two later because it made my after pains unmanageable.