From Longman Dictionary of Contemporary Englishheavy irony/sarcasmheavy irony/sarcasmVERYremarks that very clearly say the opposite of what you really feel → heavy
Examples from the Corpus
heavy irony/sarcasm• The intention is to curb the spread of package-tour baroque and heavy irony.• As the magazine with heavy sarcasm reported: Lady Betty adopted her new career with relish. 