A bottle you can get into with a can opener! (5)
I believe the answer is:
tonic
'a bottle you' is the definition.
The definition suggests a singular noun which matches the answer.
'into with a can opener' is the wordplay.
'into' becomes 'toni' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'with' says to put letters next to each other.
'opener' indicates taking the first letters.
The first letter of 'can' is 'c'.
'toni'+'c'='TONIC'
'can get' is the link.
Can you help me to learn more?
(Other definitions for tonic that I've seen before include "Keynote of a scale" , "something providing a boost" , "Producing tension of muscles" , "Fillip" , "something medicinal" .)