She sank back in disappointment when she didn't get the promotion.
with a sigh
Frequency:
50
%
He sank back with a sigh, relieved to finally relax.
against the pillows
Frequency:
45
%
She sank back against the pillows, exhausted from the long day.
Idiomatic Expressions for sink back
Phrase: sink back into old habits
Meaning: to return to previous behaviors or routines, especially negative ones
Usage: Despite his efforts to change, he found himself sinking back into old habits of procrastination.