'Burnish no bones with thy teeth for this is unseemly, neither belch thou near to a man's face with corrupt fumosity. Scratch not thy head with thy finger whilst thou art at meat, and blow not thy nose on thy napkin, where you should wipe thy hands, but cleanse it in the handkerchief. Fill not thy mouth too full, least thou perhaps of force must speak, neither blow out thy crumbs when thou dust eat. Blow not thy pottage nor drink, for it is not commendable; for if thou be not sweet in thy body, thy breath is corruptible. If you must spit, keep it out of sight; let it not lie upon the ground but tread thou it outright.'
Words of advice (predating Burns by a few centuries) in a little pamphlet of Scottish recipes 'Friends Cook Book' I got many years ago near Glencoe. There is also a helpful guide to measures. 1 1/2 Pints - 1 Lippie; 4 Lippies - 1 Peck; 4 Pecks - 1 Firlot; 4 Firlots - 1 Boll.
Happy Burn's Night and if you have to spit be sure to smear it into the carpet while your host is looking the other way.