"God bless ye merry merchants, May ye make the yuletide pay!" -- Tom Lehrer

The holidays are upon us, with their pleasant exchange of gifts -- hand-knitted sweaters from your Mom, imaginative handcrafted items from your kids and, from your cousin Myrtle, a nose-warmer.

Most of us are too reserved to indulge ourselves in the joys of owning simulated glowing logs and fake-fur toilet-paper covers. Our Puritan inhibitions restrain us from lavishing our friends with neo-Grecian lamps or dancing disco bunnies. Christmas comes but once a year and our inhibitions should take a back seat to our natural generosity and well-wishing at this time. So bring out the plastic credit cards and Buy Buy Buy!

But frst -- in case your taste for the tacky is loosely tuned -- here is a handy, practical guide. You can be sure an item qualifies as tastless if it is:

Vinyl, particularly red vinyl

40 percent sugar

Inexplicably large

Painted on velvet

Available in either upchuck yellow or obscene green

"Guaranteed" to make you laugh

Imitation, artificial or simulated

Also, anything put on the market in the aftermath of Elvis' death or John Paul II's visit is within the ballpark, as is any item designed to train small children in the art of killing.

With this guide, you can find items of dubious taste and value nearly anywhere in the Washington area. Here are some of the choicer gems: Big Yuks

Some magic shops, in addition to their magic stock, carry hundreds of items "guaranteed" to make you laugh. Here you can gather ammunition to use against the office prankster, the reunion rejuvenist, and your kid's third-grade pal who keeps leaving blob-like things on your chair.

At least one bar-supply place covers -- among other things -- the obscene end of the guaranteed guffaws. I'm not going to tell you what happens to their female anatomy swizzle sticks ($5.95) when you put them in drinks, or which finger is their "Boldfinger" gold-covered lemon juice bottle ($1.50).

They also carry a hospital booze decanter set ($25) that includes a stand and (yuk, yuk) three intravenous-feeding bottles in which you store your hooch. Tubes lead from each bottle into your glass. Very funny. Big Bucks "It doesn't matter how sincere it Is, or how heartfelt the spirit, Sentiment will not endear it; What's important is THE PRICE." -- Tom Lehrer

For only $127,174.32, Sakowitz will install a Texas-shaped swimming pool in your backyard, filled with Perrier. To order, call (800) 231-2332, toll free.

If your relative put great store in labels, impress them with a Neiman-Marcus set of bourbon and scotch flavored toothpaste (about $10). Or wrap up a Bloomingdale's gold lipstick ($6) or a simulated leftover spaghetti pin ($7 -- also comes in taco). Tacky Treats

This time of year, companies from the Great Lakes states volunteer to send teeny portions of delectable cheese "anywhere in the world" for Christmas. The cheeses come in various package deals, each with its own many-adjectived description, and some of these selections are housed in pop-corn poppers, hot-dog cookers, and other single-use containers.

If you're on the receiving end of this gimmick, why don't you empty that fake-fur-covered record box and sent it back to your benefactor with a filling of:

Smoke-flavored Spam

Squeeze Parkay

Velveeta pasteurized processed cheese spread

Powdered Hawaiian punch

Canned fruit cocktail

Cheese Curls

Ho-Ho's

Tapioca-flavored Del Monte Pudding Cup Tacky Tots

At least one store has a whole section of killer toys, including what looks like a plastic "Saturday-night special," with its own private-detective badge to sanction its use (97 cents).

For a soothing Christmas afternoon, there is an $8.68 Ertel Chain Saw that makes a "real chain saw sound."

Other activities might include the $3.48 Ants-in-the-Pants game. Very tasteful. Or Rat Race, "a madcap game of social climbing" ($7.84). Tacky Statuary

There is at least one place out in Virginia that stands as a monument to the creative use of unusual statuary. Steers, chickens, jockeys and Swiss figurines romp indiscriminantly across the roof, yard, windows and tacked-on porches and cupolas.

A quick check at this market revealed a plethora of tantalizing items including a lifesize (no kidding) brown bear with bloody teeth and an actual-size replica of King Tut's mummy case, not for sale.

For indoor statuary, there are 2-foot-high plaster pigs, dressed in macintoshes and gathered skirts, that serve as banks. Put one by your door and collect your extra change. By the time the swine is filled, you can have an eminently satisfying pig-smashing party and use the spilled cash to buy another -- $22.95. Tack Catalogue Sales "Relations, sparing no expense'll Send some useless old utensil, Or a matching pen and pencil -- 'Just the thing I need. How nice.'" -- Tom Lehrer

The matching "just the thing you need" is featured on the front of a Peoria, Ill., catalogue. There are also a number of can't-live-without-it items like an 88-cent sneaker-shaped writing pad (for "foot notes"), a $12.99 "heirloom" pocket knife decorated with a "classic" nude beauty, and a $1.99 personalized Ma and Pa chopper holder for storing dentures.

The prose of these catalogues falls into the guaranteed-laugh area of tacky.

Consider this description from one catalogue: It pictures a $49.98 "pet nest" -- a large, red affair designed to pillow your pet -- and explains that "Rover and Sweety-Puss will love this nifty, natural way to snooze." To save Sweety-Puss from unnatural snoozing? Lyrics from Tom Lehrer's "A Christmas Carol,"; Copyright (c) 1954; used with permission of Tom Lehrer