Often used to express exclamation about something, or can be used as a greeting or in agreement. But mostly used to as a reason to say something when nothing else can be said; as an ending to the convo or useless part thereof.
"Sudlup dog, sudlup"
As a goodbye on the phone...
"Sweet bro I'll be round later"
Boring convo? Just insert "Sud" and nod your head repeatedly
In a text message...
"Bro come round"
Or can also use "Hud" as word tone is more inflected, thus indicating a question:
"Hud up?" - "Whats up?"
Also, has evolved to be used as a casual greeting.
Cody- "Yo, I have nine bitches on my balls, and I drive the baddest Harley ever"!!
Ferret- To Cody- "SUD"!!!
Anyone: Let's go and sud all night long to these girls, and they better be having us!!!
"I drive a Jaguar"
Other person "SUD"
Greeting: "What are you Suds doing tonight??"