Fungal infection of ones penis.

Got the covid-19 vaccine

a disabilitating disease inflicted upon a mans purple headed warrior, often carried by ugly fat tarts, and transmitted during sexual acts.

Warning alcohol can make tarts look attractive.

The disease responsible for any man needing to become circumcised in adulthood instead of as a baby. Other medical reasons will be cited, but those are obviously all lies employed to cover the embarrassing truth.

Knob rot can be avoided by careful daily cleansing and keeping things safe during sex.

A disease men catch when they cheat on their girlfriend/wife. Will end in the knob falling off.

1.The stuff you get when you don't wash your dick...usually characterised by some bad fish stank and cheese/gangrene discolouration...
2.yeh, you can called people it too

wen sum1 is a nob rot, they usually hav a rotten nob, and its an offensive word