  Recent research showed that the rotational degree of freedom in stacking 2D
materials yields great changes in the electronic properties. Here we focus on
an often overlooked question: are twisted geometries stable and what defines
their rotational energy landscape? Our simulations show how epitaxy theory
breaks down in these systems and we explain the observed behaviour in terms of
an interplay between flexural phonons and the interlayer coupling, governed by
Moir\'e superlattice. Our argument applied to the well-studied MoS$_2$/Graphene
system rationalize experimental results and could serve as guidance to design
twistronics devices.
