Singing in pelt: awfully exciting! (5-8)
I believe the answer is:
spine-tingling
'exciting' is the definition.
(spine-tingling can mean exciting or intense)
'singing in pelt awfully' is the wordplay.
'awfully' indicates anagramming the letters.
'singing'+'in'+'pelt'='singinginpelt'
'singinginpelt' anagrammed gives 'SPINE-TINGLING'.
(Other definitions for spine-tingling that I've seen before include "Scary - exciting" , "Causing fear or excitement" .)