If stuffed into the right crevice (4)
I believe the answer is:
rift
'crevice' is the definition.
(I know that rift is a type of crevice)
'if stuffed into the right' is the wordplay.
'stuffed into' is an insertion indicator.
'the right' becomes 'rt' (abbreviation as in Rt Hon- the Right Honourable).
'if' inserted into 'rt' is 'RIFT'.
(Other definitions for rift that I've seen before include "Serious falling out" , "Fissure; split" , "Cleft in earth or breach in relationship (4)" , "Fissure in something" , "Schism (in the lute?)" .)