High tight ligs, lot's of internal penis, waiting to be pull out. If the lot theory is correct hahhaah.
If not then, I think intelligents and a person in tune with what food and water to drink, basically not putting poison into your body could help a lot when it comes to routines and gains. healthy diet healthy mind healthy body.
testosterone would play a role too, basically everything you listed above would play a role, I bet would could make a gigantic list of all the possible things that gains come down to.
For instance, each persons individual technique, the environment to which your doing your Penis Enlargement in, warm environment cold environment.
What type of equipment your using, the persons strength, dexterity, flexibility, concentration level, focus levels.
