Is my prostate thumping with aneros?

I believe so. It could mean that your prostate is awakening, a definite good sign.

Can you tell us if this thumping or beating sensation is pleasurable? And also, can you tell us how long you have been on your Aneros journey?

It's probably the arterial pulsing surrounding the rectum, which becomes more pronounced with increased heart rate.

The sensation is not really pleasure it's just a thumbing sensation in my anus but like what @thugofalltrades said it could be my arterial pulsing with my heart increases. I have not been on aneros journey that long probably about week off and on. I am seriously thinking about upgrading my Aneros Helix Classic for something a little bit bigger like the Aneros Progasm to get more of my prostate. What is your take on this?