The investigators hypothesize that two pelvic relaxation exercises will be feasible and safe to perform by subjects daily before radiation during the participant's treatment and will decrease variability of sacral slope measurements on daily port films. The investigators will observe trends in the daily variability and change in the sacral slope in each participant to determine if this could decrease variability. The investigators will compare these measurements to a retrospective cohort that did not have the exercises, but did demonstrate variability. Reducing set-up variability (which inadvertently occurs during radiation) is important to improve radiation targets and diminish potential adverse effects. The investigators will query participants for objective and subjective feedback on the exercises and record frequency and duration of the two exercises.