Dear doctors, I have good sexual desires but I can get erection through hand simulation and after getting erection also. I can acheive a full erection maintain if hand simulation but if I take my hand away it looses erection after some seconds like 15sec If i keep  I can keep my erection. If see one year back , if I have sex on mind or attract with any woman, I get erection automatically. But nowadays this is absent. Please advise how to diagnose this .what are the test to be taken and whether I have to consult urologist and sexlogist..