61 year old Paul Scott often hangs out at the Santa Monica Rings where he can be seen performing the human flag and holding it for quite some time. In this very cool video he gives instructions on the human flag using parallel bars to a random guy who just happened to be there and wanted to learn.
I’ve never seen this technique before. It relies on using legs to get upside down and then slowly laying your body out using parallel bars.
More in-depth tutorial on how to do the human flag on regular poles can be found here.