facetious
Being silly and making jokes in a playful way.
'I'm being facetious, not a total loser,' said the kid who failed the test and got a D.
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.