No morning erection weak erection while mastubating but good erection whole sex as compared ro mastubating testestorene tsh prolactin normal wt cud ca?

Physiology ok: The fact that you have normal erection during sex & your tests were normal pretty much means your physiology is intact. A further test: a Nocturnal penile tumescence test. I suspect yours would turn out normal. Your problem at masturbation may reflect refractory period effects, or insufficient excitement from a growing tolerance to whatever you use to stimulate excitement. Hope that helps.