Check when others will take a shower (8)
I believe the answer is:
restrain
'check' is the definition.
(restraining is a kind of checking)
'others will take a shower' is the wordplay.
'others' becomes 'rest' (I've seen this before).
'will take' means one lot of letters go next to another.
'a shower' becomes 'rain' ('rain shower' can be a synonym of 'shower').
'rest'+'rain'='RESTRAIN'
'when' is the link.
(Other definitions for restrain that I've seen before include "Tie up - arrest" , "Keep in check" , "Arrest - confine - subdue" , "Control - check" , "bottle up" .)