I am a novice in these matters as well, but it seems to me that whether or not one's faculties are frustrated correlates closely with the particular kind of act in which those faculties are being utilized in the first place. Utilizing the feet in the operation of a car's gas-pedal obviously does not frustrate the natural ends of the feet precisely because the intrinsic potencies of the feet include the kinds of movement being actualized: to move them about, and to interact with physical objects to the extent that they can be manipulated, ect.  (Potency, as I understand it, is a description of those powers innate to a thing that correspond with the kinds of potentials (potentials being different from mere 'possibilities') a thing can actualize).  However, if you're trying to operate the gas-pedal of a car, then it would fundamentally frustrate the utilization of the feet if one were to tie cinder blocks to them and inhibit one's control over the vehicle to the extent that it becomes impossible or tenuous to control the speed of the vehicle. 

This, as I understand it, comports with the notion that the utilization of one's faculties is always directed to ends extending beyond the mere utilization of the faculties.  Even if you are just shifting your foot from one spatial location to another, the movement of the foot is still be directed toward some end: changing the location of the foot.  Such as it is, can we not also say that utilization of the faculty is also central to the questio nof whether or a particular faculty has been frustrated? 

Utilization, here, is the operation of bringing into actualization the innate potencies of a faculty, and utilization instrumental in bringing about some end for which the faculty is directed (for the end cannot be achieved in a causal sense unless the faculty is utilized).  Fertilization of the oocyte is not achieved under typical coital scenarios unless the penis reaches a point of stimulation where ejaculation occurs, f