Dog seen in shower (7)

I believe the answer is:
pointer
'dog' is the definition.
(pointer is a kind of dog)
'in shower' is the wordplay.
I cannot quite understand how this works, but
'in' is present in the answer.
This may be the basis of the clue (or it may be nonsense).
'seen' is the link.
Can you help me to learn more?
(Other definitions for pointer that I've seen before include "Signpost - dog" , "Gun dog" , "Suggestion" , "helpful tip!" , "stick used for instruction?" .)
