If you're wondering what spooning is, the spooning definition is simply "snuggling and laying down in a position so that one person's back is to the front of the other." When thinking about how people came up with this spooning definition, think about how two spoons fit together when sitting atop one another on a table or in a drawer. Spooning is a way for loving couples to lay together in bed or on a couch, as it is an intimate way for a couple to show affection that is comfortable for both the little spoon (the partner in front; in heterosexual couples, usually the woman) and the big spoon (the partner in back; usually the man).
When many men and women think of cuddling, this spooning definition is what they have in mind. Spooning is not just a position for cuddling, though. Some couples also find it a comfortable sexual position, offering both partners the ability to lay on their sides and the partner in back the ability to explore his partner's body with his hands.
Spooning can also be entirely non-sexual. The recent trend of "cuddle parties" has fully clothed people simply seeking affection through spooning with strangers. Though those who came up with the spooning definition may not have had this in mind when describing spooning, but it is something that many people are now involved with.
To sum up the spooning definition, it is two or more people laying together, back to front, often as a display of affection.