The Centers for Disease Control and Prevention (CDC) as well as other health and public officials recommend wearing face coverings to slow down the spread of the coronavirus and protect people from contracting COVID-19. “Your cloth face covering may protect them. Their cloth face covering may protect you,” is the slogan on the CDC website. But a face mask is only as good as the protection it provides and that means wearing it properly.

It should fit snugly on your face with no gaps to allow potentially dangerous aerosols to pass through the edges. Unfortunately, if you have a narrow face, a surgical style face mask will gape and bulge, according to Travel + Leisure. One simple yet ingenious solution has been developed by dentist, Olivia Cui.

She recently shared on TikTok a simple method to eliminate those potentially dangerous gaps on the side of your face mask to make it safer and more effective. In a 60-second video that has gone viral with 3.4 million views, she shows to make the mask fit tighter in a few, simple steps.

First, with clean hands, fold the mask lengthwise in half. Make knots on either side of the elastic ear loops close to the body of the mask. Open the mask and you will see two oval holes. Push the material through those holes underneath the ear loops, and you have a tighter, safer fit.

“In absence of N95s, this might be a good alternative,” Cui said, according to Travel + Leisure.