It may take a little time before your dog is perfectly healed after a spaying surgery. She may have been wearing a cone of shame or even just a t-shirt to keep her body covered to prevent her from licking her incisions. Even post-surgery, dogs need baths. If you're spayed dog has been wearing a t-shirt during the healing process, she might be a little stinky and could require a bath. You want to take special care post-surgery just to ensure she's not causing any damage or opening any incisions.
Even if she feels like Superdog, she may be tender to the touch and a bit on the tired side after being spayed. When you go to touch, pet, or even wash her stomach your dog may flinch, or she may try to lick the area while you're washing her. Just be very cautious with her while she's healing.
Be gentle with your princess during this time of recovery. She is your baby, your pup, and she is going to want to be treated like a queen. Spot cleaning is okay, but keep your girl dry so she can heal.