Someone who has sexual intercourse with a woman who has not had sex in a while. As in, dusting hypothetic cobwebs from an unused cunt.
'Tarquin shagged the Queen? Shit, what a cunt duster.'
A 25-35 year old man who has sexual relations with a woman who is 55-105 years old. Therefore a man who wipes the dust off of an elderly woman's cunt with his wang
Reis: Dude, you fucked my great grandmother?!
Anthony: Yeah man, it was legendary
Reis: You cunt duster!