Musannaf Ibn Abi Shayba 19:249

Abu Bakr narrated to us, he said: Asbat bin Muhammad narrated to us, from Mutarrif, from al-Sha'bi, who said: The one who falsely accuses (al-qadhif) is to be whipped while he is wearing his clothes, unless he is wearing a fur garment or a padded tunic, until he feels the intensity of the striking.