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We present the first shear alignment studies and rheological measurements in the twist-bend nematic (N tb ) liquid crystal phase of odd numbered flexible dimer molecules. It is found that the N tb phase is strongly shear-thinning. At shear stresses below 1Pa the apparent viscosity of N tb is 1000 times larger than in the nematic phase. At stress above 10 Pa the N tb viscosity drops by two orders of magnitude and the material exhibits Newtonian fluid behavior. This is consistent with the heliconic axis becoming normal to the shear plane via shear-induced alignment. From measurements of the dynamic modulus we estimate the compression modulus of the pseudo-layers to be B~2kPa; this value is discussed within the context of a simple theoretical model based upon a coarse-grained elastic free energy.