Irresponsibly filmed orca eating director's head (6)
I believe the answer is:
wildly
'head' is the definition.
(thesaurus)
'irresponsibly filmed orca eating director's' is the wordplay.
'irresponsibly filmed orca' becomes 'willy' (I am not sure about this - if you are sure you should believe this answer much more).
'eating' means one lot of letters goes inside another.
'director' becomes 'd' (abbreviation eg in film reviews).
'willy' going around 'd' is 'WILDLY'.
Can you help me to learn more?
(Other definitions for wildly that I've seen before include "With enthusiasm" , "In a way that lacks discipline or restraint" , "Recklessly" .)