No teeth action...to hold cutlery to folding napkins.

I have a pet peeve about people picking their teeth in any way shape or form.
I got two great books from my friend who works at Buckingham Palace which are the Butler's Guide to Table Manners and Her Ladyship's Guide to Modern Manners. They are both entertaining reads to say the least. The Butler's Guide is written by Nicholas Clayton - a member of the The Guild of Professional English Butlers who has several years' experience in the field. On p.76 & 77 of his book he speaks about oral etiquette at the dinner table, he says:

Restaurants have supplied toothpicks for years and there are rules of etiquette for their use. There are a few more in the book but these three are my faves.

• Before gouging around with a pick, try a swill of water
• Go somewhere to probe the teeth in private, never do it at the table (SO many people pick their teeth on the tube and at dinner tables - it is just wrong!)
• Never do the thing with the flattened hand over the top lip in a failed attempt to hide the picking going on underneath, this is unparalled in its vulgarity (yes indeed)

Get the book for your friends who don't have the best table manners.