Sentimentality of school head avoiding dance (8)

I believe the answer is:
schmaltz
'sentimentality' is the definition.
(schmaltz is a kind of sentimentality)
'school head avoiding dance' is the wordplay.
I cannot really understand how this works, but
'school' could be 'sch' (common abbreviation) and 'sch' is found within the answer.
This explanation may well be incorrect...
'of' is the link.
Can you help me to learn more?
(Other definitions for schmaltz that I've seen before include "Mushiness" , "Excessive sentimentality in music or film" , "mawkishness" , "mush" , "Display of emotions" .)
