gafoon - Looking at someone's junk like it's the last piece of pizza

Looking at someone's junk like it's the last piece of pizza and you're going to eat it whole. It's like staring at a crime scene.

My brother was staring at the bus driver's crotch the whole ride.

I saw my neighbor peeking through the window like he was a peeping tom.

My friend got caught staring at the principal's legs during lunch.