Never done it but I got talking to a bunch of people that have when I developed a hog problem this summer. A lot of people recommend letting the field dressed piggy sit on ice for up to a week with the ice chest plug pulled. This will allow the meat to bleed well. They also suggest letting it marinate in cider vinegar, water and natural vanilla to take some of the game taste out.
Most important thing is proper field dressing. If it was a boy hog your friend needed to make him a eunuch as soon as he was shot. May I suggest that you make sure the pig is dead before doing this because they don't take to kindly to the procedure. The other thing like most wild animals is if he was running and real active when shot he will have a stronger game taste then if he had not been alerted and on the run . A lot of people that eat a lot of feral hog like to trap them, feed them corn for a couple of days to a week before killing it. Giving the animal a couple of days of good feed in a clean pen really improves the quality of the meat.
If you think the pork will be a bit wild you may want to grind it up and mix with domesticated pork and pork fat. The feral hog is going to be very lean.