have (one's) tongue hanging out

1. To be very thirsty and desperate for a drink. The sun was so intense that I had my tongue hanging out for a bit of water after the first mile. Can you please get me some water? Thanks so much—I just about have my tongue hanging out. Your poor dog has his tongue hanging out—I really don't think he's enjoying the heat.

2. To desire or anticipate something with great eagerness. We had our tongues hanging out at the thought of how much money could be made with such a scheme. She stared at the all-you-can-eat buffet with her tongue hanging out. The CEO practically had his tongue hanging out at the prospect of acquiring that lucrative company.

3. To be very exhausted or fatigued. He had his tongue hanging out by the end of the six-hour hike. The coach would have us run laps until our legs were ready to buckle and we had our tongues hanging out. I'm not surprised Jim's asleep after the long travel day he had. He had his tongue hanging out when he finally got here.