A 2009 thesis titled “The Separation of Shit and State, Water Sovereignty and the New Commons in Cuernavaca, Mexico," describes an undergraduate's experiences meeting and studying with some of Illich's collaborators.
One of the thesis's more interesting sentences:
It is rumored [Illich] spoke as many as fifteen languages, and never sat in a chair, as he believed they made you less mobile.
Actually, we specifically remember seeing Illich sitting in a chair, the one time we met him, in early 1985, but we also remember being surprised to see him sit on the floor while others were in chairs. It was a remarkable sight, his long legs crossed or stretched out in front of him. How limber he is, we remember thinking, almost child-like, sitting down there like that. ("I'll have two," he said when our host, a minister, offered up a cold six-pack of not-particularly-good beer in cans.)
Barry Sanders recalls seeing Illich sitting cross-legged on a couch. And there are accounts of Illich's university seminars in which he often sat cross-legged on the table around which everyone else was in a chair.