  We prove the mixing conjecture of Michel and Venkatesh for toral packets with
negative fundamental discriminants and split at two fixed primes; assuming all
splitting fields have no exceptional Landau-Siegel zero. As a consequence we
establish for arbitrary products of indefinite Shimura curves the
equidistribution of Galois orbits of generic sequences of CM points all whose
components have the same fundamental discriminant; assuming the CM fields are
split at two fixed primes and have no exceptional zero.
  The joinings theorem of Einsiedler and Lindenstrauss applies to the toral
orbits arising in these results. Yet it falls short of demonstrating
equidistribution due to the possibility of intermediate algebraic measures
supported on Hecke correspondences and their translates.
  The main novel contribution is a method to exclude intermediate measures for
toral periods. The crux is a geometric expansion of the cross-correlation
between the periodic measure on a torus orbit and a Hecke correspondence,
expressing it as a short shifted convolution sum. The latter is bounded from
above generalizing the method of Shiu and Nair to polynomials in two variables
on smooth domains.
