make up (one's) bed(redirected from make up their bed)
make up (one's) bed
1. To tidy or rearrange the bedclothes on one's bed after one has slept in it. Would it kill you to make up your bed in the morning? It only takes a couple minutes! I never feel like I've properly started the day until I've made up my bed.
2. To prepare a bed for one to sleep in by fitting, arranging, or tidying the bedclothes on it. Your brother and sister are in the two spare rooms, so I made up your bed up in the living room. Be sure to make up each guest's bed before they arrive.