Dogs do have glands that produce ear wax which contains micro-organisms that can smell yeasty, a magnet scent for any dog, especially the riper or more different the smell. And puppies just do smell different than dogs - an utterly irresistible smell, probably even in their ears, too.
Puppies have that wonderful, singular "puppy smell' emanating from all over their bodies, something indefinable, that smell, which, along with their enlarged head, "puppy eyes", foreshortened muzzles, spastic movements, activates hormones in older dogs and humans that communicates very effectively that they are vulnerable, yet not food, and apparently endears and bonds them to older dogs - and humans in the same way our own human infants do.
The puppy appearance and puppy smell combo are qualities that do all the things described above that neither maternalistic or inquisitive dogs or humans can ever seem to get enough of. I'm sure I could smell a puppy for hours and still want more! Any breed - they all smell "puppy" to me.
An older dog will roll over onto its back, exposing its tummy, to show it is fully trusting, non-threatening, often mimicking the submissive attitude of a puppy who readily upturns its tummy to older dogs in submissive respect. Your dog was likely doing that also to get down on their level instead of standing over them to show she was utterly unintimidating in nature, super friendly and inviting the puppies to play with her.
__________________  Jeanie and Tibbe One must do the best one can. You may get some marks for a very imperfect answer: you will certainly get none for leaving the question alone. C. S. Lewis |