The involuntary, unavoidably prolonged stare towards an uncommonly magnificent set of breasts once initial visual contact is made, due to size, revealing clothing or erect nipples. Often unbreakable, even when discovered and berated by the owner of the breasts.
1. "Shit dude, that chick totally busted you looking at her fine tatas." "I couldn't help it man, tried to look away but one glance and I got booblock!"
2. Harvey casually glanced over at the blond hottie in the next row at the ballpark, and seeing a gratuitous flash of nipple down her shirt as she bent over to reach in her purse, he had booblock for the rest of the game.