Here's a situation to consider. Bases loaded, one out, your team is ahead by one run. The pitcher has run the count to 3-and-2 on a particularly dangerous hitter---and don't laugh, because this has happened---the manager takes him out at that point, and there you are, coming into the game. It's the eighth inning, say, and there you are, on the mound, facing that 3-and-2 count.
So what do you do now?
Call time. Call your catcher out to the mound for a conference. Now here's the thing: the catcher may know something about that hitter that you might not know, so it's a good idea to discuss the situation. What is that batter up to? Has he positioned himself to drive one to the opposite field? Or is his intention to wait you out for a walk, which would force in a run and tie the game? Or---is there a possibility that, even with that count, the SQUEEZE is on? Talk about these things with your catcher, and more likely than not you two can decide on what to throw to this batter. One pitch. Maybe you can strike him out, if you throw something he's not looking for---or you can get him to pop up to the second baseman. The important thing is to trust two things: your stuff, and your catcher.
And remember---if the batter decides to bunt, and the bunt goes foul, it's strike three. Inning over, and you've pitched out of a tough spot. If the darn thing is in fair territory, grab the ball and fire to the plate to get that lead runner. And you've pitched out of a tough spot. 8)