Ninja sext

When you send someone a naked picture of themselves that they don't know you took. Especially useful as a pick-up technique.

"Dude, Anna just sent me a ninja sext!!"

"What do you mean?"

"She just sent me a picture of MY penis, but I've never been naked in front of her? WTF??"

"True ninja broseph. She's a ninja sext master."