Sandbox sharer (8)
![Ross](/clue/static/ross-mug.min.png)
I believe the answer is:
playmate
'sandbox sharer' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for playmate that I've seen before include "My palate (anag.)" , "Game participant" , "fun chum" , "Companion for fun" , "Chum in recreation" .)