Go into school for talk (6)
I believe the answer is:
speech
'talk' is the definition.
(I've seen this before)
'go into school' is the wordplay.
'go' becomes 'pee' (both can mean to urinate).
'into' is an insertion indicator.
'school' becomes 'sch'.
'pee' going within 'sch' is 'SPEECH'.
'for' is the link.
(Other definitions for speech that I've seen before include "Verbal communication" , "Communication by word of mouth" , "The business of talking" , "Speaking faculty" , "Oration to an audience" .)