As many commentators have noted "feet" was often a Bibical euphamism for genitals. Circumcision was widely practiced in Palestine and Egypt as symbolic castration giving credit for fertility of the marriage to the patron god. IE. the children of the cultists are 'children of god' . Here the wife cuts here son and bloodies her husbands organ with it so as to declare him a "bridegroom of blood' while he is yet uncircumcised. Moses is never said to be circucised.
The story appears to me to be very disconnected with not only the context but the theology of the major contributors to the OT. I suspect the piece is a very early legend, perhaps unconnected to Moses that was inserted with modification to explain why Moses was never circumcised.