Ponyboy doesn't seem to enjoy the violence that the other greasers indulge in, but then again he doesn't shy away from it. The violence in the novel, at least from Ponyboy's point of view, all seems to come for a point of necessity. he is either defending himself or his friends. He does not seem to take any amount of pride or joy in fighting. Indeed, after he threatens a particularly aggressive soc away with a broken bottle, he cleans up the glass shards so as not to hurt anyone.
So in that regard, "How does Ponyboy feel about fighting?" I would have to say that he views it something that has to be done, but not something that he enjoys. To him, fighting is simply something to do. Self-defense is needed, naturally, but it is not something that he can enjoy.
He feels that fighting is bad and doesn't like it.