A bunker is a hazard in golf. If your ball is in the bunker, you have a bit of a problem.
When someone makes a beeline for something, it means you head straight toward it, quickly.
The person is referring to a specific bunker, a bunker that his ball usually goes straight to. In other words, he often doesn't do well on this hole, hitting his ball too frequently to this bunker. He personifies his ball a little by suggesting the ball is heading to the bunker on purpose.
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