As in life, accidents happen and cosmetic injuries occur, but it is the guts of a car, the engine, transmission, and brakes that will decide if it will be happily driving down the road or sitting in the junkyard.
This process is called the veno occlusive mechanism and it results with penile erection.
You may have a penis that s grown to its full size as early as age 13 or as late as age 18.