大比丘三千威儀 1.42

1.42

When on the bed, there are five matters: first, one must not yawn loudly; second, one must not click the tongue, spit, or laugh loudly; third, one must not sigh and brood over worldly affairs; fourth, one must not recline leaning against the wall; fifth, when wishing to rise and sit, one should do so at the proper time. If the mind wanders unsettled, one should blame oneself as at the beginning and immediately rise.