An effusion is an explosion of something, usually words, ideas, or emotions. A popular singer might inspire an effusion of cheers from her devoted fans.
Mozart is known for the effusion of notes he could produce at a moment's notice — and all without erasing. A heated argument can produce an effusion of words from both sides. The volcano's eruption was an effusion of smoke and fire. The verb form of the word is effuse: After the high-school musical, your mother effused about your singing. Her comments were an effusion of praise. Your father, on the other hand, was less effusive — but he did like the dancing.