Shared out presents he helps to deliver? (6)
'presents he helps to deliver?' is the definition.
(Dasher is one of Santa's reindeer)
'shared out' is the wordplay.
'out' indicates anagramming the letters (out can mean wrong or inaccurate).
'shared' is an anagram of 'DASHER'.
(Other definitions for dasher that I've seen before include "Sprinter like one of Santa's reindeer", "A sprinter among Santa's reindeer", "Fast runner", "A sprinter, perhaps a Santa's reindeer", "Member of team pulling together".)