Even if you could ride a flamingo, it would be a very uncomfortable and dangerous experience. Flamingos have small feet and thin legs that are not designed to carry the weight of a human. If you were to try to sit on a flamingo's back, you could unbalance the bird and cause it to fall over or fly away. You could also end up with nasty cuts and scrapes from the flamingo's sharp beak and claws.
Flamingos are beautiful and fascinating birds, but they should be admired from a distance. Please respect flamingos and their natural habitat and do not try to ride them.