  We consider scenarios in which the annihilation of self-conjugate spin-1 dark
matter to a Standard Model fermion-antifermion final state is chirality
suppressed, but where this suppression can be lifted by the emission of an
additional photon via internal bremsstrahlung. We find that this scenario can
only arise if the initial dark matter state is polarized, which can occur in
the context of self-interacting dark matter. In particular, this is possible if
the dark matter pair forms a bound state that decays to its ground state before
the constituents annihilate. We show that the shape of the resulting photon
spectrum is the same as for self-conjugate spin-0 and spin-1/2 dark matter, but
the normalization is less heavily suppressed in the limit of heavy mediators.
