Like a shag on a rock
Alone and conspicuous.
Person 1"Where did everyone go?"
Person 2"Left me standing here like a shag on a rock."
Where it's from
A shag is a cormorant, a seabird often seen alone on rocks.

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While you're here
Extremely busy. Can be sarcastic about someone who isn't busy at all.
Extremely thirsty. Also used for weather that has not seen rain in months.
Completely full, usually after a big feed. Sometimes used for very drunk.
Showing off and very pleased with yourself.
Almost impossible to find.
Extremely happy.