"Aw, shucks!" (3)
'aw shucks' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for gee that I've seen before include "Wow!" , "Goodness" , "Mild expression of surprise, may go before whiz" , "that's something" , "Exclamation of surprise" .)
(Other definitions for rats that I've seen before include "deserters" , "were piped away" , "Mild oath - sewer residents" , "Annoyed expression" , "Tells" .)