i used to have thoes problems but ( idk how long you have done it) but the more u do it the more u have control over ur orgasm. i mean u just cant flex them the second b4 you cum, it dosnt work like that. what i would suggest is that you take some time to your self a couple times a week, masturbate and try to stop. what i have found is that, if you are really paying attention, you can feel the semen as it travels to the penis. thats when you can put the breaks on. that buys you alot of time if u stop it b4 it gets to the base of the penis. but also it dosnt sound like you are exercising throughout the day. the pc is like any other muscle and has to be exercised. so get a program and do it thoughout the day because another factor is that your pc muscle isnt strong enough in the first place. so try all that and i cant wait to hear back.