plunge in

phrasal verb
1
to jump into something, especially with force
شیرجه زدن, پریدن به‌داخل
2
to start doing something in an enthusiastic way, especially without thinking carefully about what you are doing
دل به دریا زدن, با شور و شوق اقدام کردن, بی‌گدار به آب زدن
She was about to plunge into her story when the phone rang.
He's always plunging in at the deep end .
3
to push something quickly and with force into something else
فرو کردن
Bring the water to the boil and plunge the vegetables in.
She plunged the knife deep into his chest.