Linguica

In addition to using an inefficient inch-by-inch process to design my penis, my penis tend to get bloated to absurd sizes because, since I know where everything is, there is far less exploration factor.

Is there a one-size-fits-all a method for determining how long a penis really needs to be, or is it best to go with an assumption of what routes the partner will or will not immediately see and estimate how long they will take to reach the climax based on that? What are some factors I should take into account besides the possibility of partner petit mort, how an unfamiliar partner might approach certain encounters, what the partner already knows, etc?