... Enjoyed with others, its contents go quickly (4)
I believe the answer is:
hare
'go quickly' is the definition.
(hare can mean to run fast)
'enjoyed with others its contents' is the wordplay.
'enjoyed with others' becomes 'shared' (eg shared some food with others).
'its contents' indicates the central letters (the letters contained by the inside of the word).
The middle letters of 'shared' are 'HARE'.
(Other definitions for hare that I've seen before include "'You can't run with the . . . . and hunt with the hounds'" , "Fast runner" , "Sort of rabbit" , "who often got stiff?" , "Run with great speed" .)