We introduce an analog of dual equivalence for the affine symmetric group which shares many nice properties with dual equivalence on permutations. In particular, we use this relation to define a D graph structure on starred strong tableaux, defined by Lam, Lapointe, Morse and Shimozono, which preserves an additional statistic called spin. As a corollary, we obtain a combinatorial proof of the Schur positivity of k-Schur functions, introduced by Lapointe, Lascoux and Morse. Moreover, there are strong connections between these D graphs and those constructed for Macdonald polynomials which may shed light on the Lapointe-Lascoux-Morse conjecture that Macdonald polynomials expand positively on the k-Schur basis. This is joint work with Sara Billey at the University of Washington.