Pulling hard and letting go of the back of someone's bra, causing pain in tight-bra wearers and confusion in loose-bra wearers. Variations are twimming costume (twanging a swimming costume), twickers (twanging knickers)and many more.
Someone of such devout religiousness, they appear to be a member of God's brigade, known as the God Squad. Brings fear to the heart of many atheists. Members are often unfortunate-looking.
Watch out, the God Squad is coming for you!
Seriously, it's like every teacher at this school is a paid-up member of God Squad.