en_tn/sng/01/12.md

lay on his couch

"sat eating his special meal." This probably refers to one of the couches on which people would lie around a table at a banquet. You could translate using the common word for what people do with their bodies when they eat special meals.

nard

an oil that people got from the expensive nard or spikenard (valerian plant with small pink or white flowers) and used to make their skin soft and to have a pleasant odor.

emitted its fragrance

"gave off its good smell"