Dude-tang is a description of a male who is over sixteen but younger than you and is hot like lava in the microwave.
Any particularly handsome lad over sixteen can be classed as Dude-tang, except red heads. Ranga-tang is almost unheard of bar a few well known cases e.g Rupert Grint
Dude-tang is rarely achieved but often lusted over.
Twin Dude-tang or multiple brothers who are all Dude-tang are Bro-tang and older men are just plain Tangy.
It is duel purpose term that can be used to express a mans gayness or a woman's sluttiness. Essentially you pointing out that that person has sex with an abundance of men.
Jake: Look at those guys holding hands...
Mike: Fuckin dudebangers.
Sam: I slept with jenny last night.
James: That's not much of an accomplishment seeing as how she's a dudebanger and all...