It sounds much worse than it is, they insert a device up your back passage, it has needles etc within it and they take samples of your prostate by going through the wall of your bowel.
When I had it done it was a chrome plated bit of kit with a red light on the end (imagine if the Terminator had a penis?)
There isn't too much pain, you get to hear clicks, which sound much like a stapeller, each time they take a sample.
It has an inbuilt scanner which allows the doctor to see your prostate in great detail, when I had it done I chatted with him, and he was able to tell me there and then, that I actually had cancer. Of course you have to wait for the lab results for definitive confirmation with Gleason grades etc.
Afterwards you will find yourself bleeding from the anus and penis, in my case this went on for some weeks, fresh blood at first, in your urine, stools and semen, I am guessing that some blood must puddle within you, for I noticed it got progressively darker in the weeks following the biopsy, we used to joke about me having 'spunk of the devil'.
So there it is, a bit discomforting, like getting shafted by the Terminator, and you will bleed for a few days afterwards, but by Christmas you will be back to normal.
Best of luck.