What does the word "lasengi" means? It occurs in Franketienne's 'Dezafi' in the sentence "Ou pran latranblad lasengi."

Latranblad Lasengi, not an everyday H. Creole word, means an all of a sudden uncontrollable shake resulting from anxiety, surprise or fear.  It's 'theater' language.
Haitian Creole ↔ English Reference, Look up Haitian Creole and English Words