Miche : not. f. A miche is a large, round country bread.
In the plural: the loaves are the buttocks (north) or the breasts (south), or the buttocks.
Pinching a woman's loaves: pinching her buttocks.
Put down your loaves: sit down. Put your loaves here!
Tighten the loaves: push yourself.
He left, squeezing his asses: he left with his tail between his legs, ashamed.
To have the loaves at zero / the loaves that make gla-gla / the loaves that are well done: to be very afraid, to be scared to death.
Curdle the loaves: be cold.
To have hot asses: to be scared to death.
To swarm the loaves: to hurry.
Get your asses ready : hurry up.
To earn his crust with his loaves: to prostitute himself.
Big ass: big breasts.
Go to the loaf: go soliciting.
The expression "Curdle the loaves / the wheels": To be (very) cold.
And to begin with, why do we say curdle? The image would have appeared at Céline in the 1930s. We know that curdle denotes coagulation under the effect of cooling or fermentation. Imagine then that it is so cold that your blood curdles inside your veins. Curdle would then mean "to cool to the point that the blood can no longer circulate, so it freezes".
Now let's move on to loaves. Take a nice loaf of bread, a large ball split lengthwise. Wouldn't it remind you of a nice pair of buttocks separated by a nice vertical smile?
It is in any case the image which, in the slang of the end of the XIXth century, called loaves buttocks. And to reinforce the metaphor, a little before, in the middle of the same century, the miche also referred to the moon, to which the buttocks are often compared.
Finally why the grindstones ? There, the explanations are much less affirmative. This name for buttocks, which appeared in the middle of the XNUMXth century, could be due to the analogy of shape with the rounded top of a haystack. The expression is strictly equivalent to "freezing your buttocks" or "freezing your ass".