 This clinical trial aims to evaluate the efficacy of testosterone replacement therapy on the frequency of recurrent priapism in patients with SCD. The sub-hypothesis that testosterone T replacement to achieve serum T concentrations at a target range reduces recurrent priapism will be tested. This aim will involve subjective and objective assessments of priapism occurrences and erectile ability including priapism inventory instruments, standardized questionnaires of erectile function EF and quality of life, and RigiscanTM erection monitoring in a 3.5-month pilot investigation. 