Willy movements

Willy movements is basically when you know the gender of someone sitting next to you, without looking at them, as you can sense the willy movements. It can also be used in many other ways, like when your friend accidentally touched your moving willy, when you're running, etc.

"Hey, did you see who you got sat next to in lesson?"
"Nah, I didn't look, but I know it's a boy."
"How?"
"I could sense the Willy movements."

"Hahahaha, I accidentally touched your willy, I could feel the willy movements"