Boy in a whirl (4)
I believe the answer is:
eddy
This clue is a double definition.
'boy' is the first definition.
(I've seen this before)
'a whirl' is the second definition.
(I know that whirl can be written as eddy)
'in' is the link.
(Other definitions for eddy that I've seen before include "making the rounds?" , "Spin" , "Twist" , "current running back" , "Whirl (in fluid)" .)