Going for a grog run and paying with coins.
Shortened to 'skummer'/'skumming'.
(If you're purchasing rum, it becomes a 'rum skum run', which becomes increasingly difficult to say each time you go for one.)
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Dude 1: man, grog shop closes in 15 minutes and I can't find my 20 bucks!
Dude 2: fuck the 20! grab all the coins you can, we're going for a skum run.
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Bro A: 1.. 2.. 4.. 6.. 7.. 7.50.. 8.. 8.50.. 9.. 9.50.. 10.. 10.50.. 10.70, 10.80, 10.90, 10.95.... 11! SKUMMING TIME!