Strong drink makes us sleep quietly in schools (8)
I believe the answer is:
schnapps
'strong drink' is the definition.
(schnapps is a kind of strong drink)
'us sleep quietly in schools' is the wordplay.
'us' becomes 'ch' (I can't explain this - if you can you should believe this answer much more).
'sleep' becomes 'nap' (a nap is a short sleep).
'quietly' becomes 'p' (p for piano and quiet).
'in' means one lot of letters goes inside another.
'schools' becomes 'SS' (an abbreviation for school written twice).
'ch'+'nap'+'p'='chnapp'
'chnapp' placed into 'ss' is 'SCHNAPPS'.
'makes' is the link.
Can you help me to learn more?
(Other definitions for schnapps that I've seen before include "Strong gin-like drink" , "Strong spirits drunk in northern Europe, strong on consonants" , "Strong clear spirit drunk in Germany" , "Strong alcoholic drink from the Continent" , "Various strong spirits drunk in N Europe, consonant heavy" .)