We present an analysis of in-situ thermal ion measurements from a cusp auroral sounding rocket. Using a forward modeling procedure, we find most-probable thermal ion temperature and parallel (field-aligned) bulk flow velocity along the trajectory. Spatially and temporally intermittent fine-scale structure in upflowing/downflowing features in the dayside cusp ionosphere are presented. We show that the observed ion temperatures are consistent with Joule heating expectations if spatially and temporally intermittent drivers and responses in the dynamic cusp environment are considered. Additionally, a forward modeling procedure for the ion data interpretation is improved and a sensitivity analysis is presented.