i don't really understand your question. first the testicles do not store or make semen. the testicles make sperm and the sperm is stored in the epididymis. the prostate gland makes the semen. second abstinence from ejaculation does not increase "sensitivity" in the penis so i am not sure what you are asking.
how long does it take for testicles to be completely full of semen? at that point it should be at maximum sensitivity? . the goal of this question is to understand how to attain abstinence since i'm a single divorced man. i figure if i can understand the science of this question it will allow me to have a goal in mind (for lack of a better term) that will give me hope in knowing that my penis will be as sensitive as it can be at that moment of which the semen is completely full. . at that point i think it will ease my mind and allow myself to just get used to being that sensitive all of the time. thank you.