DEAR MISS MANNERS: Can you please tell me when it is appropriate to lick or tuck the flap of an envelope on a card? What is the thought behind either?

I'm a tuck person, unless money or a gift card is enclosed or when mailing; my daughter is a lick-every-card person. Please end our 20-year battle!

GENTLE READER: Only if you promise that you and your daughter have the next topic of debate lined up. Miss Manners would hate to be the cause of the zest going out of your conversations.

Have you noticed that wedding invitations come with two sets of envelopes, but only one of them is gummed? This is because envelopes are sealed when they will be handled by strangers, as the outer one is, but the inner one is not.

The strangers, in such cases, are our friends at the post office. But if an envelope is handed from its sender to its intended recipient, or put in the hands of a friend to be delivered, the flap is only tucked in, the latter instance being a sign of trust that your intermediary will not peek.

So basically, you win. Miss Manners' condolences to your daughter.

DEAR MISS MANNERS: This is a first for me. My husband and I have been invited to a renewal of a couple's wedding vows. There are two squares on the return card. One says we will attend (and how many); the other is my "first": "We cannot attend and wish to extend our congratulations." Our "congrats" were written for us. Is this the new normal for responses?

Also, we didn't recognize the names of the Mr. & Mrs. and asked our kin and friends. We finally discovered the "Mrs." is my sibling's granddaughter, whose married name I didn't know. This is, apparently, their first anniversary. Yes, they're very young. Any comments?

GENTLE READER: It seems part of the trend whereby wedding hosts are taking over the functions of their apparently untrustworthy guests.

After all, why do people who issue invitations feel that they have to answer them as well, with a form requiring only a check mark and a signature? What is more, many of these cards refer to declining as expressing regret, without consulting the actual feeling of the recipient. And few couples nowadays would dream of letting their guests choose what to give them as presents.

So Miss Manners supposes that they might as well offer themselves congratulations on behalf of the guests. As brides and bridegrooms like to say: It's their day. Guests have increasingly become supernumeraries whose direction and lines the beneficiaries supply.

DEAR MISS MANNERS: How does one reply to an invitation while one is in mourning, from deep mourning to almost the end of a mourning period?

GENTLE READER: By thanking the would-be hosts and saying, "I'm not going out socially now; I'm in mourning."

Miss Manners is afraid that you must keep repeating this while they lecture you about how the living must go on living, the deceased would have wanted you to go out, it's time to achieve closure, and so on. Please don't let it get to you.

(Please send your questions to Miss Manners at her website, www.missmanners.com; to her email, dearmissmanners@gmail.com; or through postal mail to Miss Manners, Universal Uclick, 1130 Walnut St., Kansas City, MO 64106.)

DEAR MISS MANNERS: While at a family reunion on the opposite coast, I took my brother to the airport 100 miles away. I called a friend (female) who lives 20 miles from said airport, whom I met years previous, and asked if she would like to tag along.

Though we have kept in touch, I have never as much as kissed this woman and haven't been in her presence since we met.

When we arrived to pick her up, she was incensed that my brother didn't immediately get in the back seat, knowing that she was coming out, and said that, as a woman, etiquette would require him to do so.

I am not in a "relationship" with this woman, so to me it seems that would just label her as a friend, which has no gender limitations.

Since my brother was the one I was performing the service for, it seems as if the front seat was his, and it was his choice to relinquish or not (which he did after an intense spat, only out of respect for me).

The aftermath has caused mild friction between my brother and me, as well as impacted my relationship with my platonic female friend. What would etiquette dictate as the proper protocol?

GENTLE READER: Etiquette dictates that you look at this situation for what it was, and not confuse it with your and your friend's peculiar ideas about gender. Miss Manners hardly knows which claim is more askew -- that gender is the paramount factor here, or that gender counts only when there are kisses.

Your friend should have sat next to you because you had proposed the driving time as a visit, and it is awkward to hold a conversation from the back seat. Had you wanted to spend the time chiefly with your brother, you should not have invited a guest.

So you both behaved badly, as did your brother, squabbling to keep what all of you apparently consider a place of honor. Had Miss Manners been in the car, she would have been tempted to say, "Now, children, behave yourselves, all of you, or I'm turning this car around right now."

DEAR MISS MANNERS: Is it proper to send a sympathy card to the family of a person who committed suicide?

GENTLE READER: No; a heartfelt letter.

At least Miss Manners hopes that this is the point you wanted settled. Surely you are not questioning whether this family is in need of sympathy.

DEAR MISS MANNERS: If you tell someone that dinner is at 6 p.m., that you will sit down to eat at 6 p.m., what time should you expect your guests to arrive?

GENTLE READER: Late. If they followed your instructions, they would all be backed up on the front porch, and it would take a while to get them all through the door and to the table.

Miss Manners is no proponent of lateness, especially when it is ridiculously called fashionable. But have a little regard here for human nature and traffic. If you want to serve dinner at 6, invite your guests for 5:15.

(Please send your questions to Miss Manners at her website, www.missmanners.com; to her email, dearmissmanners@gmail.com; or through postal mail to Miss Manners, Universal Uclick, 1130 Walnut St., Kansas City, MO 64106.)

DEAR MISS MANNERS: If you are at a gathering of friends and family, is it rude to go into a corner and fall asleep?

GENTLE READER: If you look as if you are doing so on purpose, yes. So unless you are old enough to produce smiles when you say, "I'm afraid it's my nap time," or young enough to have a parent make that announcement for you, you should not make obvious preparations for sleeping in comfort. No stretching out on the sofa or plumping its pillows.

Dozing off in place is another matter. Comfort is out of the question then, not only because of the crick developing in the neck, but because of the noise your relatives will make arguing whether this is a symptom of illness that must be taken seriously, or the result of your having overdone the food and drink.

Given those alternatives, the now-alert sleeper may want to claim rudeness, apologize, and try to look interested in the conversation.

DEAR MISS MANNERS: I was wondering if it is proper etiquette to say "excuse me" after yawning.

GENTLE READER: That would be admitting that you had yawned. A truly alert person would twist the yawn into a smile. But, then, Miss Manners supposes that a truly alert person would not be yawning.

DEAR MISS MANNERS: I know about the existence of dessert spoons and forks, their placement and use. But I still don't understand how to eat with them.

Eat the cake with the fork and leave the spoon alone? Eat the ice cream with the spoon and leave the fork? If there's a sauce, do I -- or may I -- eat with the fork and mop up with the spoon? Do you ever use both at once?

GENTLE READER: Indeed you do: That is the default method at formal meals, used for every dessert except those when it would be ridiculous, such as -- as you have noted -- ice cream without cake, or cake without ice cream.

Miss Manners offers the two-utensil dessert setting as proof that etiquette, far from trying to trick hungry people by confusing them about what flatware to use, generously provides the tools to get the job done.

DEAR MISS MANNERS: I was taught from childhood to tuck a corner of the napkin into my shirt collar to protect the front of the shirt while eating. I usually do not follow this custom for casual dining, but I usually do when wearing a tie or a suede coat or the like because it can be very effective at protecting the garments and avoiding an expensive dry-cleaning bill.

My lady friend, however, tells me that the tucked-napkin look is not something that is attractive or socially acceptable, and that I should avoid this custom lest I appear to be a rube.

On occasion I also have used the device of unbuttoning one shirt button and tucking the tie inside the shirt, usually when dining with other males. Your comments on the appropriateness of these usages would be appreciated.

GENTLE READER: It is to your credit that you remember that early childhood lesson. But what about the subsequent lessons?

Were you not taught, as your motor skills developed, to refrain from overloading your fork or spoon and to aim carefully, so that a bib was no longer necessary? If your parents neglected this, your lady friend seems ready to teach you, Miss Manners gathers. Barring some unfortunate medical condition, a gentleman is supposed to be able to eat neatly enough to avoid splattering himself.

(Please send your questions to Miss Manners at her website, www.missmanners.com; to her email, dearmissmanners@gmail.com; or through postal mail to Miss Manners, Universal Uclick, 1130 Walnut St., Kansas City, MO 64106.)