The World Toilet Organization tells how:
"At exactly noon on November 19th, gather your family, friends, classmates, colleagues and everyone you know to squat in public for 1 minute in support of World Toilet Day. This drives home the point "where would you go?" and how people without toilets are forced to go in public places. Notify the press to attend. Upload a photo of you squatting to encourage others to join."
For more details see The Big Squat: A Movement for the Toilet-less.
If squatting is not for you, watch the S*it Song by Larke. The GAS campaign promotes unglamorous and difficult issues. It tries to get people to talk about "toilet issues." Why? Until people are not embarrassed to talk about poop, toilets, and diarrhea, the 2.5 billion people without toilets are unlikely to get anyone to listen to help them get toilets.