noun, noun or participle which takes 'suru', intransitive verb
sleeping together; sharing a bed
Refers to two or more people sleeping in the same bed or futon, often with a connotation of intimacy or closeness. Can be used literally or euphemistically.
幼い頃、よく祖母と共寝をした。
When I was little, I often slept together with my grandmother.
旅館では友達
At the inn, I ended up sharing a bed with my friend.