facetious
Trying to be funny but being a total pain in the ass about it.
'I'm being funny, not a total loser,' said the kid who made a joke about the teacher's bald spot and got sent to the principal's office.
During the meeting, the manager said, 'I'm being facetious, not a total idiot.' No one believed him.
The kid said, 'I'm being facetious, not a total loser,' while the teacher was writing him a detention.