The Goddess's Hands (or in French, La Main de Deesse) is a concept introduced in the second arc of the anime set in Paris.
But the warmth they provide is not enough to knead soft bread like the Brioche. A soft feminine grip is required, flexibility that only comes to those who have trained since childhood.
Kawachi tries to hide that he doesn;t with only regular flexibility.
The strongest Goddess hands apparently belong to Gran though, who trains a combination of extreme strength and delicacy by walking around on them.