“I should be a postage stamp. That's the only way I'll ever get licked.”

Simplified Meaning:

The quote is a clever way of saying that the person feels unbeatable and incredibly confident. They believe they are so strong or talented that the only way they could be defeated or 'licked' is if they were something as everyday as a postage stamp, which you literally lick to stick on an envelope. Imagine a top athlete who is so good at their sport that no one can beat them in a match. This athlete is saying that because they're so skilled, no opponent will ever win against them. The only way they could experience defeat is if they were a postage stamp being licked to seal a letter, which is clearly not possible for a human. In everyday life, this kind of confidence can be inspiring. It suggests having a very positive outlook on one's abilities and not being afraid of challenges. However, it’s also important to remain humble and be prepared for any situation, as overconfidence can sometimes lead to unintended consequences. For example, the confident athlete might still train hard despite their belief in their abilities, ensuring they stay at the top of their game.