Stuff I leave in place (3,3)
I believe the answer is:
pig out
'stuff' is the definition.
('pig out' can be a synonym of 'stuff')
'i leave in place' is the wordplay.
'leave' becomes 'go'.
'in' means one lot of letters goes inside another.
'place' becomes 'put' ('put' can be a synonym of 'place').
'i'+'go'='igo'
'igo' going inside 'put' is 'PIG OUT'.
(Other definitions for pig out that I've seen before include "feast" , "To eat a lot may" , "Eat too much food" , "go on a binge" , "gorge" .)