sit on a tack
An expression of contempt or dismissiveness directed at someone, particularly in the…An expression of contempt or dismissiveness directed at someone, particularly in the case of disagreement.
Meaning
2 senses(colloquial, dated, idiomatic)An expression of contempt or dismissiveness directed at someone, particularly in the case of disagreement.
I don't care what he thinks! He can just sit on a tack!
"Go sit on a tack!" she said, angrily.
Used other than figuratively or idiomatically: see sit, on, a, tack.