This is the Trinken Lid, a plastic lid that snaps onto the top of a beer can and, when placed in a paper cup (not included), disguises your brewski as a piping hot cup of gogo juice. Alternatively, just pour your beer in a coffee cup like a normal person who can't be bothered to hunt down their Trinken Lid every time that want to sip a cold one under the radar. Trust me, I've been doing it at work for years, and nobody is the wiser. "Everyone knows you're drunk." No they don't. "You threw up in the copier." That bright light gives me vertigo. "That doesn't even make sense." I'd like to see you come up with a better excuse on the fly when you're as wrecked as I am.
Keep going for a few more shots.
Thanks to David W, who agrees coffee cups are modern humanity's secret stashes.