People are big on this "behind the ear" shot business, but it has a couple of problems. If the hog is sideways to you, you can literally shoot behind the ear and have the shot go through nothing but muscle. The ear marks the rear point of the skull. So if you shoot behind the ear and the hog is perpendicular to you or quartered toward you, then you will likely only get soft tissue and be relying on hydrostatic shock to drop it. With a sufficient caliber, that will often work, no doubt, but I have seen it fail as well. There just aren't any vitals "behind the ear."
If the hog is quartered away, behind the ear works well because the trajectory should have the round continuing into the skull.
If you are going to shoot "behind the ear" then do so, but 1-2" lower than the ear. That will put you MUCH closer to the spine. The spine is located more centrally in the neck that many expect.
Remember, it isn't just about placement, but placement, trajectory, and penetration. It isn't where the bullet impacts on the exterior of the body that is important, but what structures it damages while penetrating through. So trajectory really is critical.
Aim small, hit
small is a much better motto to follow. Missing, small or large, can be bad.