Burlesque as a literary device is a description of serious topics and problems deliberately in a funny, sometimes even in a vulgar way.
Burlesque synonyms are: parody, caricature, travesty, imitation, satire.
Read the classic poem about love:
Roses are red,
Violets are blue,
Sugar is sweet,
And so are you!
A burlesque version of this poem (actually a parody) looks like:
Roses prick your fingers,
Violets make you sneeze,
Sugar fills your veins with fat,
It’s best you stick to peas!
Contrasting examples of literary burlesque are Alexander Pope’s The Rape of the Lock and Samuel Butler’s Hudibras.