"呑山臥酒" means to enjoy drinking in the mountain with nature. It is from the original phrase "呑山臥酒" written in classical Chinese literature“雲仙雑記".
It means to fully enjoy spring season and comes from that people's act who taste how amazing
and beautiful the spring is, enjoy drinking sake and become comfortable to lay down. We pull on a
word with " 山(mountain)" instead of " 花(flower)".