Squirm on TV and lie about dummy act (13)
I believe the answer is:
ventriloquism
'dummy act' is the definition.
(act with a ventriloquist dummy)
'squirm on tv and lie about' is the wordplay.
'and' is a charade indicator (letters next to each other).
'about' is an anagram indicator.
'squirm'+'on'+'tv'+'lie'='squirmontvlie'
'squirmontvlie' with letters rearranged gives 'VENTRILOQUISM'.
(Other definitions for ventriloquism that I've seen before include "Voice-throwing" , "Throwing one's voice" .)