Pulls (4)
'pulls' is the definition.
(I know this)
This is the entire clue.
(Other definitions for tugs that I've seen before include "Tows" , "Yanks" , "Pulls hard" , "Pulls in a jerking manner" .)
(Other definitions for lugs that I've seen before include "Slangy ears" , "Drags the worms by its ears" , "Pulls" .)