i had robotic prostrate surgery 16 months ago and still can t achieve an erection sufficient for sexual intercourse. I m 74 soon to be 75 and try self stimulation almost daily. I want to have sex and was wondering how long it will be for my nerves to regain their effectiveness for erection. My urologist said he spared the nerves as best he could..... Ive been taking 5mg Cialis and using a VED which though messy will create an erection but it wont hold even with the ring after erection. I ve tried 100mg Viagra as well and was considering asking for the injection medication to see it that would work.....