  We use a generalization of chiral perturbation theory to account for the
effects of flavor twisted boundary conditions in the Breit frame. The relevant
framework for two light flavors is an SU(6|4) partially quenched theory, where
the extra valence quarks differ only by their boundary conditions. Focusing on
the pion electromagnetic form factor, finite volume corrections are calculated
at next-to-leading order in the chiral expansion and are estimated to be small
on current lattices.
