He bent over at the waist exposing the top and the whole left side of his head. (But he had a good chin.) He used a cross-arm defense, which renders your left hand (which is protecting your body) useless in that position. (But he had a good, short counter right.) He didn't have fast feet or great movement, was more of a slow-footed plodder from the waist down. (But his feet were usually in position to punch.) Didn't really move his head, he just swayed his whole torso side to side to try to avoid shots (and often ate them anyway). He was a guy whose style worked for him, for the most part. But he was never a great trainer because his style couldn't be adopted by just anyone. It worked for him because his strengths compensated for the style's deficiencies. If you didn't have a quick, short right hand, really good power, and you couldn't take a great shot (or even a decent one), it would probably be the absolutely worst style you could adopt.
There are few in the history of boxing whom I enjoy watching more than the Ol’ Mongoose. He was like a living encyclopedia of boxing right in front of you. Was he the perfect fighter? No. But few were better and he darned sure wasn’t shy about stepping in the ring with anyone to see if he could beat them.