"Y'all come," you said last January, "y'all come to visit us at the beach." Or perhaps it was the country house or the mountain cabin or the farmhouse in the Dordogne or the Italian villa. Whatever the invitation, it seemed safe to make it when the world was glazed with ice and snow; by the greening of the seasons, the generous gesture would be forgotten.

Ha. It is now July and all the y'alls have come, every single one of them showing up on your doorstep with a suitcase and a list of things they want to see, meals they will not eat, and an insatiable desire to claim the attention of their host.

More than one frantic owner has moved down in the world, deliberately dumping the house with endless guest rooms and buying a place less competitive with the local Hilton; and one architect, after seven months when the guest room was always occupied, sold up lock, stock and barrel and built himself one enormous room, with a teeny, tiny guest house stuck way away on the edge of the property. Hospitality, but at a distance.

Since selling the guest rooms and the house to which they are attached is an extreme solution, here are some other suggestions for smoothing the difficult relationships between houseguests and host:

Do not issue invitations when you are lingering over the port. The warm glow of friendship engendered by a good meal and several glasses of wine does not usually endure. If you must be the gracious host while in your cups, always make the invitation conditional. "I would like you to come and stay, assuming, of course, that Wilhemina hasn't made other plans." If there is no Wilhemina in your life, invent one. Come morning one will be devastated to discover that, indeed, other plans have been made.

If you are the guest, never take seriously an invitation issued after a particularly good dinner. If it was sincere, it will be offered again.

If you are the host, do not invite anyone to come and stay without telling him of the disadvantages. If you are way off in the country and the only transportation is a car, and the only amusements miles away, warn the guest. If you don't, the guest will moon about, speaking yearningly of those faraway pleasures, until you feel forced to interrupt whatever you're doing and act as chauffeur.

And do not turn your car over to a guest unless your insurance covers other drivers. This is not being a stick in the mud; accidents do happen and the guest doesn't want to discover that the damage isn't paid for any more than you do.

Think twice before offering a guest the use of a living room couch unless your schedules are so closely coordinated that when one goes to bed, all go to bed and when one awakes, all awake. Otherwise you will be irritated by having to tiptoe around that lump in the living room, and the guest will be irritated by the lack of privacy.

If the household contains small children or animals, a guest should realize that they live there and are not going to go and stand against a wall for the whole of the visit. People who don't like kids or canines, should stay somewhere else.

Guests should try to fit into the rhythm of the household, which means not hogging the bathroom or using up all the hot water with a two-hour shower, offering to help and actually doing it, and not assuming that the invitation included full maid service. One woman who had invited a German friend to stay for two weeks at the beach, and who provided daily lunches and dinners, was shocked by the form of the thank you: "I admire the casualness of you Americans," her guest said in a snide farewell. "How wonderful to be so relaxed that you don't feel it necessary to make breakfast for your guests."

When you are ready to leave, unless there is a maid, ask the hostess where the clean sheets are so that you can change the bed. She may (and probably will) say not to bother, but at least the offer will have been made. And if there is a maid or a cleaning woman and you have made extra work, leave a tip.

If you have not taken your host and hostess to an extravagant thank-you dinner, or to the theater or the opera, send a thank-you gift. By the time you leave, you will know what they need, and what is appropriate to their home. And though you can always pick up something in a nearby town, country houses and seaside houses soon become crammed with the slim pickings offered in the local shops and bought as gifts by grateful guests.