The Miller Lite Punch Top Can featured a secondary, smaller tab on the lid that you puncture with a key or pointed tool. This aided airflow to reduce glug and enable a faster pour. Basically allowing you to shotgun a beer.
To demonstrate this, we had a spokesman and his trusty sidekick use anything and everything possible to open a Miller Lite and educate beer drinkers on how to unlock this feature.
And yes, thanks to the Miller Lite legal team, we also had to legally prove all of the methods shown worked.