Learn how to say Convulsing correctly in English with this tutorial pronunciation video.
Oxford dictionary definition of the word convulse:
(transitive) to shake or agitate violently
(transitive) to cause (muscles) to undergo violent spasms or contractions
(intransitive) often foll by with (informal) to shake or be overcome (with violent emotion, esp laughter)
(transitive) to disrupt the normal running of (a country, etc) ⇒ student riots have convulsed India
C17: from Latin convulsus, from convellere to tear up, from vellere to pluck, pull