I feel like a bull
My informant has been saying this phrase for as long as he can remember. He is the creator of the phrase, but it has become folklore because his entire group of family and friends now use the saying and associate Tom with it.
When Tom says the phrase I feel like a bull, he is referring to his current state of mind and how he feels. He grumbles the phrase as well, to add to the effect of the saying, and sound like more of a bull. Tom uses this phrase when he has done something that he is proud of, or just feels great in general. For example, when Tom will go on a run, a swim, or even have an exceptionally good day at work, he will grunt, I feel like a bull.
Toms interpretation of his own proverb is very literal. In a herd of cattle, the bull is the leader. He is the ultimate king, maintaining the macho position in the herd. Tom only says this phrase when he is completely on top of his game. When this occurs, it is as if there are no other males around. Tom says that this phrase makes him feel like he is really on top of the world. The reason it is important to him is because he really cherishes his good health and treasures his life so much. To everyone that knows Tom, this phrase does not represent a self-absorbed character, but an appreciative one.
I think it is great that Tom created this phrase. People that do not know Tom may interpret it to think he is boasting, but it really is about his appreciation for life. Tom takes very good care of himself, and is very grateful for everything that he has.