Affixes (7)
'affixes' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for pins that I've seen before include "With needles, they create a tingling sensation" , "Wire fasteners" , "security codes" , "Stocking fillers" .)
(Other definitions for fastens that I've seen before include "fixes" , "Attaches firmly" , "Fatness (anag.)" , "Bolts" .)