Etiquette when meeting Pope Francis

Some lucky people will get to meet the pope face-to-face during his visit to the United States. So how do you handle a once-in-lifetime opportunity like that in terms of etiquette and protocol? Pope Francis is different from most popes and is known to put protocol aside.

"What he really wants to do is to act like Jesus would act or act like he imagines he would act," said Dr. Julie Byrne, the chair of the Catholic Studies Department at Hofstra University. "Putting his hands on everybody that he possibly can."

Byrne said the dos and don'ts of pope etiquette date back to ancient protocol.

"It involves kissing his ring, it involves not touching him unless he approaches you first," she said. "However this pope is someone who is so friendly and he regularly dives into crowds."

Aside from formally referring to Pope Francis as "Your Holiness" or "Holy Father," standing when he enters the room, and applauding if there's a crowd, for the most part it's all fair game.

"Off limits may be fist pumping the pope, kissing the pope or slapping him on the back," Byrne said. "These are things maybe not to do for the pope."

"Nothing he will do will surprise me," said Gary Krupp, appointed by Pope John Paul II as a knight of the Order of St. Gregory. He knows and has met the present and past popes. He said Francis is a people pleaser and his free spirit and modern ways have connected him to all faiths.

"He takes the selfies, he's on Twitter, he doing all the things of modern communications, which are very positive," Krupp said.

A pope's personality has a lot to do with his history. The previous two popes both grew up during the war. Francis grew up during hostile times in Argentina. He has been known to interact with crowds and make spontaneous stops along the way.

"Be yourself, smile, if you have a baby hand it to him," Krupp said.

While it's highly unlikely the hundreds of thousands of people who get to see the pope will have an opportunity to put these tips to use, the pope being who he is and what he has done in the past, you just never know, Krupp said.