Mackin' Off
Mackin' off is when you're so full of yourself, you think your bad decisions are actually good.
I'm mackin' off like I just invented the wheel, but I still can't ride a bike.
He's mackin' off like he's the best at everything, but he can't even cook toast.
She's mackin' off like she's the queen of the universe, but she can't even find her phone.