Flexible cystoscopy, widely used in urological practice, is better tolerated than rigid cystoscopy but can cause discomfort in men, particularly at the membranous urethra. This study investigated whether standardized pressure bag irrigation reduces procedural pain during flexible cystoscopy METHODOLOGY Ethics approval (2023/PID00688) and trial registration (ACTRN12623000799651), was obtained. Male patients undergoing Flexible Cystoscopy at Westmead Hospital, Sydney were randomised into 3 groups: control (gravity drainage with simulated bag squeeze), pressure bag set at 350mmHg, and manual bag-squeeze. Exclusion criteria included chronic pelvic pain, history of urethral or bladder neck stenosis, use of analgesia within 24 hours, and long term IDC. Primary outcome was mean VAS pain scores post procedure, and secondary outcomes assessed using PROMIS surveys for; pain intensity (1a), pain inference (6a), and emotional distress-anxiety (4a). RESULTS 68 patients (29 pressure bag arm, 18 bag-squeeze arm, 21 control) were recruited. For the primary outcome, both the pressure bag and bag-squeeze groups reported lower mean VAS pain scores compared to the control group (1.8, 95% CI [0.97 – 2.63], and 1.9, 95% CI [0.95 – 2.85], respectively). For secondary outcomes, the pressure bag group reported lower scores for pain inference compared to the control group (I: P<0.001, II: P=0.0002, III: P=0.0001, IV: P=0.021, V: P=0.036). The pressure bag group had lower scores for overwhelming worry (P=0.023), while the bag squeeze group scored lower on uneasiness (P=0.015). CONCLUSION Standardised pressure bag irrigation reduces procedure pain and emotional distress during flexible cystoscopy, supporting its adoption as a standard of practice.