pack sand
When someone tells you to pack sand, they’re calling you a total loser. It’s like the seafaring version of being called a f***ing idiot.
My cousin got called to pack sand, and he yelled, 'I’ll pack sand in your mouth!'
At the bar, the guy said, 'Pack sand, you f***ing sea slug!'
He told me to pack sand, and I told him to eat a seagull.