Of all the Shadow Types, the Pig is, perhaps, closest in viewpoint to the Wraith it belongs to. Those who are gluttons indulge themselves at any expense - including others - and don't care about anything else, so long as their gross appetites are sated. Needless to say, the Pig agrees with this epicurean viewpoint, and acts as a spiritual enabler as the Wraith explores new vistas of stuffing herself silly.

The Shadow would like nothing more than for the Wraith to wallow in her appetites like a horribly corrupt Roman Emperor, demanding everything and denying nothing. A perfect day would consist of the Wraith lying back, and not needing to lift a finger to have what she most desires brought around to her, in excess. And while being dead means that certain pleasures are more difficult to procure, the Shadow is nothing if not full of ideas on how to get it here, or bring the Wraith there.
 
Wraiths who exhibit the symptoms of the Pig look disgusting: they are often rolling with fat, and unsightly blemishes and warts that might indicate an STD or two. {Wraiths can't catch them, of course, but tell that to the Pig}. They are -2 on all Social rolls, except when leading the willing into depravity or gluttony.
 

Heart's Thorn: Bacchanalia
 
The Shadow knows what it wants, and knows how to get it. Extra dice will be given to the Wraith in the pursuit of their shared, gargantuan appetites, so long as the Wraith is willing to undertake a choice morsel or two on the Shadow's behalf. Lending dice to tempt others into joining at the table, or arranging for the banquet, itself, are also within the Shadow's purview.

As for the shared power, the Wraith is able to get others to join her in shared gluttony. A Contested roll is made, with the Wraith's Presence + Angst pitted against the others' Composure or Resolve {whichever is most appropriate} + Eidolon. Those overcome by the Wraith's persuasion must join her in whatever she's doing, and can only break free with the expenditure of 1 Willpower and a sucessful Morality check. If they don't succeed in this, or don't care to try and break free, they run with the Wraith on her wild spree of gluttony for an entire Scene.