Adjective: to describe unwashed, smelly, infected or otherwise unpleasant female genitalia. Comes from the contraction of the words 'Festival/Infested' and 'Box' to describe female genitalia.

See also blue waffle. (Note VNSFW)
'Word up Tarquin, I just got back from Coldplay at Glasto'!
I saw Hattie up the front looking well peng, I'd love to tap that snatch'

'But Terrence, I hear she never washes that thing. Must be a proper festibox down there in the jungle blud.'
by Contiikikiki October 8, 2011
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