Snuggling or sleeping together with no real intention of having any intimate time. Can turn sexual by accident but generally just a platonic relationship for the mutal benifit of enjoying sleep while being close to someone.
More common in winter, where single males and females attempt to keep warm. Sometimes wrongly interpreted as Friends with benifits, No strings attached snuggling wether platonic or not generally has no after-sleep awkwardness or strings.
Early in the morning James see's Sally leave Harry's room -
James: "Woh - did Harry and Sally fuck last night ?"
Jon: "No man - they just slept together - no strings attached snuggling. they do it all the time".