I guess it's a Blarney Boner?

Definitely can. It's a muscle. Muscles either work, cramp or tear. You can break a penis, bend it, similar to cramps in legs or arms but without bones. Pain is intensified in genital area due to no bones and smaller area. Think of a very strong stomach cramps, but in penis or even vaginal canal, and of course in same region anal cramps when your butt doesn't relax at all. That can put you in hospital and in some cases these muscles can inflame or swell, and healing takes time due to bodily functions. Google for more, it's quite interesting part of anatomy. The pain is no joke.

It's not a muscle. The hardness is due to erectile tissue being able to engorge with blood and keep it there for a while.