The best thing that helped me was using a curved G-spot vibrator. Slide it in about 2" deep, with the angle pointed up. Turn it on and sit back and relax for 15 minutes. Don't worry if you don't feel a thing on the prostate. Do this twice a week, at least a day before a aneros session. This really got my prostate going and I still do this weekly, it's like a supercharge for the prostate.
Peace out.