  A general iterative method proposed some years ago for the description of
relativistic collapse, is presented here in comoving coordinates. For doing
that we redefine the basic concepts required for the implementation of the
method for comoving coordinates. In particular the definition of the
post-quasistatic approximation in comoving coordinates is given. We write the
field equations, the boundary conditions and a set of ordinary differential
equations (the surface equations) which play a fundamental role in the
algorithm. As an illustration of the method, we show how to build up a model
inspired in the well known Schwarzschild interior solution. Both, the adiabatic
and non adiabatic, cases are considered.
