I have noticed that many hospitals are not requiring the rolling anymore according to several patients' comments.
It is likely because the consensus among a medical community stated "when considering other practical issues for BCG administration, the Task Force determined that it is not necessary to rotate patients every 15 min post BCG instillation". See the section What are the most important practical aspects of administration of BCG?
www.ncbi.nlm.nih.gov/pmc/articles/PMC5557323/
The detail explanation of why the rotation is not required is mentioned in the paper by Dr. Ashish Kamat of MD Anderson and others.
txcercit.org/Files/publications/23540779.pdf
"An interesting practice among some urologists is to have patients lie recumbent during the instillation period and to have them rotate every15 minutes in an attempt to evenly expose the entire bladder surface to BCG. Although well intentioned, this rotisserie method does not seem to have any basis in the scientific literature. The elastic nature of the compliant bladder suggests that it changes size to accommodate the volume of fluid inside. Therefore, unless the instillation was incorrectly done and a large air pocket was introduced in the bladder, serial turning of the patient is not necessary. It is the authors’ practice to have patients lie recumbent for several minutes
after instillation of the BCG and then to allow them to ambulate normally during the 2-hour retention period."
Still, it would not hurt to rotate just in case there is a large air pocket as it could be the case. But, the consensus by urologists says we do not have to worry much on rotating.