One heading to nightclub to tuck into brew or a Bud (5)
I believe the answer is:
china
'a bud' is the definition.
(I've seen this before)
'one heading to nightclub to tuck into brew' is the wordplay.
'one' becomes 'i' (Roman numeral).
'heading to' says to take the initial letters.
'to tuck into' is an insertion indicator.
'brew' becomes 'cha' (I can't justify this - if you can you should give a lot more credence to this answer).
The first letter of 'nightclub' is 'n'.
'i'+'n'='in'
'in' put into 'cha' is 'CHINA'.
'or' is the link.
Can you help me to learn more?
(Other definitions for china that I've seen before include "Porcelain ware and country" , "friend or companion" , "Land" , "Delicate porcelain form Orient?" , "porcelain cups?" .)