Stick one's nose in, exposing party regularly (3)
I believe the answer is:
pry
'stick one's nose in' is the definition.
(I've seen this before)
'party regularly' is the wordplay.
'regularly' indicates alternate letters (regularly take one letter, leave next etc.).
The alternating letters of 'party' are 'PRY'.
'exposing' is the link.
(Other definitions for pry that I've seen before include "Inquire intrusively" , "Snoop, poke about" , "Intrude" , "act curiously" , "Stick nose into other's business" .)