It's not just when they sleep, although she's almost asleep here. But Wynny's tongue could even fall out sideways when whe was eating, although I can't imagine how it didn't get bitten.
The Greyhound racing industry in Australia is responsible for many thousands of Greyhound deaths every year. This is the personal story of one of those poor dogs, but at least this one had a precious few weeks of normal life at the end.