I Am A Nurse. When I Administired Bcg Nine Years

I am a nurse. When I administired bcg nine years ago, the patient laid in a bed and rotated their body every 15 minutes for 1 hour. After the hour, the patient voided and went home. My uncle is going to start treatment next week. They will instill the medication and discharge him home. He was told to void one hour after administration. Why doesn't the patient rotate to coat the bladder anymore?