Musannaf Ibn Abi Shayba 33:732

Muhammad ibn Fudayl narrated to us, from al-Walid ibn Jumay', from Abu Salamah, who said: The companions of the Prophet, may God bless him and grant him peace, were neither slackers nor did they feign death (i.e., they were not lethargic or overly ascetic to the point of lifelessness). They would recite poetry to one another in their gatherings and mention the affairs of their pre-Islamic era (Jahiliyyah). However, if one of them was pressured regarding something concerning his religion, the whites of his eyes would rotate as if he were a madman.