to act bashfully or hesitantly, fidgeting or squirming because of shyness or embarrassment.
初めての発表で子供がもじもじしている。
The child is fidgeting nervously during their first presentation.
彼は好きな人の前でもじもじして、なかなか話しかけられない。
He squirms in front of the person he likes and can't bring himself to talk to them.
もじもじせずに、はっきり言ってください。
Don't hesitate—please say it clearly.