Musnad Ahmad 31:37

Sufyan ibn 'Uyaynah narrated to us, from al-Zuhri, from 'Ata' ibn Yazid al-Laythi, from Abu Sa'id al-Khudri, who said: "The Messenger of Allah (may Allah bless him and grant him peace) forbade two types of clothing and two types of sales. As for the two sales: they are *al-mulamasah* (touching) and *al-munabadhah* (casting). And the two types of clothing: *ishtimal al-samma'* (wrapping oneself in a garment leaving no opening for the arms) and *al-ihtiba'* (sitting with one's knees drawn up to the chest) in a single garment, with nothing of it covering one's private parts."