Heisenberg Uncertainty Principle 

You're never really sure when you are going to get laid.

The party was hopping but the Heisenberg Uncertainty Principle was is full play so who knows what will happen.

Heisenberg Uncertainty Principle by SaintAmbrose July 29, 2022

Heisenbro Uncertainty Principle 

Combination of "Heisenberg Uncertainty Principle" and "bro." A bro cannot be both a bro and a boyfriend/husband at the same time. If he's with other bros, he acts one way: usually vulgar and rude. If he's with his girlfriend/wife, he acts another way: sweet and charming. He can never act exactly like a bro if he is with both bros and his girlfriend or wife.

One often observes the Heisenbro Uncertainty Principle at weddings.

Heisenbro Uncertainty Principle by Ae5Ea8 March 2, 2015