xí dì mù tiān
以地为席以天为幕。指在露天席地而卧。
唐·韩偓《惆怅》诗:“何如饮酒连千醉,席地幕天无所知。”
席地幕天作定语、状语;用于书面语。
have the earth as one's mat and the sky as one's tent