bori-bori
The sound and motion of scratching an itch vigorously. Can also describe crunching on hard food like rice crackers.
💡Scratching a mosquito bite absent-mindedly — 'He was bori-bori scratching his arm during the lecture.'
虫刺されをぼりぼりと掻いてしまった。
I scratched the bug bite bori-bori without thinking.
Stop ___ scratching that — you'll make it worse!
○○掻いたら余計にひどくなるよ！