Cluin - Thank you for a new enrichment of my wee Scottish vocabulary; I can't use it here because I just finished reading this thread, but you're free to use it when singing. Better now: Do me the favour and transfer the entire song into Scottish; I would be honoured to see my feeble work in Burns' own language.
Final version: And so they drank the live long night into the mornings dawning light, the clear and shining morrow. They sang and sprang so merrily and lived without a sorrow.
Note: People who prefer not to jump over tables and benches when drinking are invited to use danced instead of sprang.
With many thanks to my learned and distinguished contributors: Drink, sing and spring [or dance]!