Many people enjoy telling stories about their experiences (real and imagined) to any interested audience. Good storytellers are always entertaining and fun to listen. A well-crafted and presented tale is almost always welcome. Narratives can range from short, quick and humorous anecdotes through to the longer tall stories with mini-adventures that build to an interesting conclusion.
A pool hustler who has a talent for storytelling can use this very creatively during a competitive match. He probably has a personality that can't stop performing. A pool match is an excellent opportunity since you are a captive audience of one. There may also be railbirds who can selectively become an audience. Stopping him probably requires rope, a gag, and a couple of assistants.
An amateur hustler doesn’t understand the necessity of good presentation and timing. If he’s really bad, all he accomplishes is a reputation for rambling nonsense.
An experienced gamesman applies his storytelling skills at two levels. The first level is to be a continuous distraction. If he can reduce your focus enough to miss a few shots during a match, which can be all he wants to do. The second level is the timing of his best stories or jokes – usually when you most desperately need to buckle down and apply all of your concentration on winning.
He might make minor concessions to normal table courtesies – i.e., not talking when you shoot, etc. He might advance a story between your shots. But he also is talking while he shooting. Beginning from the moment he takes over the table, his mouth continues talking – pretty much on automatic. He knows his stories so well, that it doesn’t affect his abilities to analyze table layouts and make good shot choices. He might, momentarily, stop talking while he aims and strokes the shot.
The hustler, as an expert storyteller, uses this shark very purposely. He is fully aware that when you are paying attention to his stories, you are also distracted from playing your best game. He can, when you have to make the right shot choice, ensure that part of his storytelling occurs just when you come to the table. The effort to move your attention from his story into the mindset to do a proper table analysis takes time also burns up some of your brain energy. This means you lose valuable thinking time needed to consider multiple options.
If he does an effective job of modifying your will to win, the level of importance originally intended for the match is reduced. The game becomes more of a casual, pass-the-time-of-day effort instead of the deadly serious duel to the death attitude needed to win. As long as he can keep you from thinking carefully, that is all the edge he needs.
It's always enjoyable to listen to a good story. But in a match, you must devote the whole of your thinking to the game. Only this level of focus ensures that good and proper decisions can result in your best chances to win.
You can use the moderately active response of using the hand up, palm out, traditional "stop" signal when you are shooting. When used, hold that pose until he stops talking. Then restart your game. Repeat as needed. Unfortunately, this requires continuous attention to every time he starts talking.
There is a high-road approach that might help stop this shark. Begin with a courteous and firm request that he not talk while you are shooting. If he is unintentional on affecting your game, simply telling stories as a matter of personality, this would work. If he is an evil-doing mind-bender, any agreements are void 15 minutes later.
The low-road approach is more effective. If he is a storytelling addict, you can trick him into losing. Whenever he starts a story, be very encouraging and appreciation. The effect of having an interested listener encourages him to put more passion into his delivery. This gets him to self-shark (always a nice turnaround).
Another tactic is to ask questions about the storyline. For example, "And then what?" "What does <character> do next?" "Are you sure that is what happened?" Continuous interruptions cause confusion and handicaps his efforts, with little effect on you.