What stops trick Birthday candles from being blown out?

a trick candle is when a person blows one out, it simply re-lights itself in a few seconds. Normally there is a burning ember in the wick that causes a ribbon of paraffin smoke to rise from the wick.The key to a re-lighting candle is to add something to the wick, so that the ember is hot enough to ignite. That way the candel can relight...