I'm guessing that the term to 'spoon' someone is derived from actual spoons. Being of the same shape a spoon will naturally fit snugly into another spoon rather like a person snuggling up to curl around their significant other like two spoons, a perfect fit.
If it is derived from cutlery then my husband and I are a knife and fork.
For me there are a number of issues with spooning.
If you are the Spoon-er you will be faced with the problem of what to do with your arm. The free arm curls about your lover quite happily but, unless the other arm can be unscrewed and left on the side, it has nowhere to rest comfortably. It can go under your partner's neck but there will come a moment when it's necessary to try to extract this arm without waking your slumbering partner. You can squeeze this arm down your side and get pins and needles or you can put it in the really uncomfortable position above your head without jabbing your spouse with your elbow.
Should you be spooning someone with wind then there will be a moment when they fart in your lap and the stench ripples up between your pressed bodies to be released up your nostrils.
If you are the spoon-ee and like me have long hair you will find that your lovely curly tresses, much admired during the day become a choking hazard when spooning at night.
Generally humans do not fit together like spoons. It's also a safety hazard. Valuable seconds could be wasted disentangling ourselves if there were a fire or intruder in the middle of the night.
It's like being clamped in a hot, sweaty human vice.
Before marriage I spent most of my life being free to sleep as I choose and never felt the urge to wrap myself in a heavy, human sized teddy bear.
For me, the answer would definitely be not to spoon or as a compromise, set a time limit to finish spooning before pins and needles, sleep or leg cramps set in.