A vaguely female member of the pikey plague
. One that is kept in a permanent state of pregnancy by either close family members or random passing strangers.
The milk produced by such a monster is considered highly toxic by all but the hardiest of pikey tykes, being infused with an assortment of hard drugs, and is thought to contribute considerable to the damaged state of the suckling thugs in later life.
At the centre of every pikey plague outbreak, you will find, nestled away in a 11th floor council flat, at least a dozen or more dairy pikeys pushing out their deformed proteges like there's no tomorrow.
A dairy pikey should not be confused with with a common or garden, fat pikey, although careful examination may be required to tell the two apart.
scenarion: Taking the air along brentford
(me): Fuck me, if I'm not sorely mistaken, THAT is a dairy pikey