Dipping ones phallus into hot sauce, oil or broth. Usually for some sort of sexual depravity. Other possible uses for fondugling are: painting (with a penis instead of a brush), cleansing (as if soap isn't strong enough), making a penis more inviting (for the man with a unhandsome, scared, too small, too large member or bad personality).
Paul was so 'fuck ugly' and had such a bad personality that he decided, in order to get a woman to touch his penis, he'd resort to fondugling, but, to no avail, instead, the young lady laughed, took a picture of his fully fondugled member, called the police and had him arrested. Paul spent a week in jail teaching 'big Tony' all about fondugling.