Yearns to be seen around facilities in underwear (4,5)
I believe the answer is:
long johns
'underwear' is the definition.
(I've seen this before)
'yearns to be seen around facilities' is the wordplay.
'yearns' becomes 'long s' ('long' can be a synonym of 'yearn').
'to be seen around' is an insertion indicator.
'facilities' becomes 'john' (I've seen this in another clue).
'longs' enclosing 'john' is 'LONG JOHNS'.
'in' is the link.
(Other definitions for long johns that I've seen before include "Underpants with legs" , "Thermal underpants" , "warm clothing" , "Some underclothing" , "Warm underwear" .)