Perhaps tablet's best after drink (6)
I believe the answer is:
laptop
'perhaps tablet's' is the definition.
(tablet is a type of laptop computer)
'best after drink' is the wordplay.
'best' becomes 'top' (top can mean the very best).
'after' says to put letters next to each other.
'drink' becomes 'lap' (to lap is to drink up).
'top' after 'lap' is 'LAPTOP'.
(Other definitions for laptop that I've seen before include "Kind of computer" , "device?" , "Aid for businessman" , "Type of computer" , "Portable computer" .)