とばかり（に）
Usage
is a construction that is often used to show that something is being done 'as if to say (A)', or 'seeming that (A)'
Examples
ランナーが通り、ここぞとばかりに声援を送りました。
The runner passed, and as if to say ‘Now’s the time!’, I let out a cheer.
「おまえも黙れ」とばかりに手でテーブルを叩いた。
She slammed the table with her hand as if to say 'Silence!'.