Oblige one Italian to interrupt very loud tease (4,3,2)
I believe the answer is:
make fun of
'tease' is the definition.
(to make fun of someone is to mock or tease them)
'oblige one italian to interrupt very loud' is the wordplay.
'oblige' becomes 'make' (if you're obliged, you're made to do something).
'one italian' becomes 'uno' ('one' in Italian).
'to interrupt' indicates putting letters inside.
'very loud' becomes 'ff' (musical abbreviation).
'uno' going within 'ff' is 'funof'.
'make'+'funof'='MAKE FUN OF'
(Other definitions for make fun of that I've seen before include "Ridicule or tease" , "Mock" , "Deride, cause others to laugh at (4,3.2)" .)