"What's up, unittttt!"
"That kid's a fucking unit."
It's all about the emphasis on 'unit'. The usage derives from both 'dude' and 'cock'. 'Dude' is more often complimentary while 'cock' is sometimes just 'cock' and other times 'cock' is derogatory.
"Ahhhh, unitttt!!!! What's up, kid?!?!?"
"She couldn't handle my gigantic unit."
"He's the biggest fucking unit."
Also derives from Randy Johnson, also known as 'The Big Unit'. The first known usage of the modern 'unit' terminology was by a Boston man, himself a big unit because of his height, strength, and ability to crush beers.