FORT WALTON BEACH, Fla. — “Men cannot know that we wear makeup,” Jahkara Smith says at the beginning of her first makeup tutorial, her face a mask of concern. “It will all be over for all of us. The universe will stop. Reproduction will cease.”

Pulling out foundation, she says: “The first thing you want to do is hide the fact that you have human flesh.” She begins to rub the product vigorously into her skin, extending it to her neck. “They’re looking at necks now,” she says. “They’re learning.”

As the video continues, Ms. Smith, who is 21 and goes by Sailor J on YouTube, layers on more and more makeup, all while dispensing mock wisdom for living in a patriarchal society .

On concealer: “If it rubs off on anything, they’re going to know you’re a witch.”

On eyebrows: “If they are off-kilter by a centimeter, everyone will know that you’re a lying wench.”