You don't stick his penis up your urethra during frotting. You wrap your foreskin around it.
You can not safely stretch tires.
The urethra can be subject to narrowing. The stretch methods are to assure the passage stays open and allows for urine to pass through.
It is just rubbing against each other without penetration.
It sets the speed at which Highway Safety Engineers determine can be driven safely on that stretch of roadway.
When the bladder is full of urine, stretch receptors in the bladder wall trigger the 'need to go' reflex. The detrusor muscle that surrounds the bladder contracts. The internal urethral sphincter relaxes, allowing for urine to pass out of the bladder into the urethra. Both of these reactions are involuntary. The external urethral sphincter is voluntary. It must be relaxed for urine to flow through the urethra and outside the body.
the urethra
The prostatic or membranous urethra
prostatic urethra
Dilating the urethra is done when there is a stricture (abnormal narrowing) of the urethra in order to make the urethra wider.
The urethra.
The urethra; it is located between the clitoris and the vaginal introitus in the vulva.
urethra basically near the penis but its the urethra