What is the Hadith that mentions that Aisha—may Allah be pleased with her—used to place stones or something else in her mouth when addressing men so that they would not be tempted by her voice?

It is not known in the Sunnah or in the biography of the Mother of the Believers Aisha anything that proves a woman placing her hand or a stone in her mouth when speaking with non-mahram men. Al-Alusi reported from some of the Mothers of the Believers that they would place their hand over their mouth when speaking with a non-mahram man, but placing a stone in the mouth is unknown and contradicts the leniency of Islam and the guidance of the Salaf.