Drink tea and sherry regularly (6)
I believe the answer is:
chaser
'drink' is the definition.
(as in a shot and chaser)
'tea and sherry regularly' is the wordplay.
'tea' becomes 'cha' (cha is a type of tea).
'and' is a charade indicator (letters next to each other).
'regularly' indicates alternate letters (regularly take one letter, leave next etc.).
The alternating letters of 'sherry' are 'ser'.
'cha'+'ser'='CHASER'
(Other definitions for chaser that I've seen before include "second drink" , "Pursuer - of beer after whiskey?" , "A drink like beer after whisky" , "Milder drink taken after a stronger one" , "Drink following another of a different kind" .)