Switch positions with French art teacher in High (3,4,4)
I believe the answer is:
off ones head
'high' is the definition.
(both can mean crazy or intoxicated)
'switch positions with french art teacher' is the wordplay.
'switch positions' becomes 'off on' (off and on are positions on a switch).
'with' means one lot of letters go next to another.
'french art' becomes 'es' ('is' in French - 'art' can mean 'is' eg 'thou art').
'teacher' becomes 'head'.
'offon'+'es'+'head'='OFF ONES HEAD'
'in' is the link.
(Other definitions for off ones head that I've seen before include "Cap in hand is so" , "wasted" , "deranged" .)