Taint-rippling fart
A fart so loud and powerful that not only will you worry if you've sharted, but the shock waves created by the booming sound, will ripple the skin along your taint.
Peggy Sue got the shock of her life. With Pete going down on her after their meal of chilli with beans, she let rip with what Pete later described as a taint-rippling fart. He could see the skin of her taint ripple with the explosion emanating from her arse.