大比丘三千威儀 2.97

2.97

There are further five matters: first, when the assembly discusses affairs, one must not speak jokingly; second, one must not spit thoughtlessly on the ground in front; third, one must not hold one's knees with one's hands; fourth, one must not support one's head with one's hands and doze off; fifth, one must not open one's mouth wide and yawn.