as useless as tits on a bull
tits are not used on a bull because bulls do not produce milk. they are still there though.
a person that cannot do their job properly may be referred to as= as useless as tits on a bull.
as useless as tits on a bull
Extremely useless, to the point of absurdity. Used when extremely frustrated.
"Darn it, the screws are stripped. These are as useless as tits on a bull!"