  This article presents a new model-independent constraint for bouncing black
hole geometries. Using the thin shell formalism, this constraint sets a bound
on the minimal allowed radius of the time-like surface of the collapsing star
at the bounce. It follows from this bound that the shell always bounces in an
untrapped region or precisely on a trapping horizon. This constraint is of
purely kinematical origin as it descends from the continuity of the metric
between the geometries describing the interior and exterior of the collapsing
object so that it is completely model-independent. The second part of this work
investigates the conditions under which an effective extension of the
Oppenheimer-Snyder collapse can describe consistent bouncing black hole
solutions. We show that on top of the previous kinematical constraint, an
additional dynamical condition has to be satisfied in order for the model to
admit well-defined black-to-white hole solutions. As expected, this second
condition turns out to be model-dependent. The resulting class of models
describing bouncing compact objects are characterized by three parameters for
the star (mass, initial radius and density) and two quantum parameters
descending from the UV-completion of the exterior and interior geometries. The
solution space contains (1) bouncing stars and (2) bouncing black holes and (3)
a new class of astrophysical objects which alternate between a bouncing star
and a bouncing black hole. Finally, we provide an explicit construction of a
black-to-white hole bounce using the techniques of spatially closed LQC and
discuss the novel properties induced by the presence of the inner horizon in
this new framework. This generic framework lays down the foundation for
interesting phenomenological investigations concerning the astrophysical
properties of these objects, as well as a novel platform for further
developments.
