Face Wiping Etiquette
Q: Should one wipe another's face? (While at a dinner party a guest was speaking and failed to see the subtle hints that there was some debris on the corner of his/her mouth. A person reached across with their table napkin and wiped their face.)
A: This is one of those behaviors that depends on the relationship between the people involved. A spouse might do this for husband or wife especially if there is some incapacity. Wiping someone else's face is a tricky thing to do, because it is either a very intimate gesture or one that shows condescension. If a person can get close enough to wipe another's face, he or she can get close enough to whisper in his or her ear. This would be the preferred way of handling the situation, and one should even be circumspect about this. But at a dinner party where everyone is seated, the situation is more complicated; a whisper might require someone to rise from the table. You might try a ruse de etiquette and make an excuse that you are going to the restroom. Take that opportunity to discreetly whisper in the ear of the oblivious person.