"We spend thousands of dollars on condoms in a week," says Left Eye with a straight face. T-Boz and Chilli, on the other hand, can't suppress their smiles. After all, that weekly condom bill is a sign of success. Collectively known as TLC -- for the acronym, not the aphorism -- these early twentysomethings have seen their debut album, "Ooooooohhh ... On the TLC Tip," go platinum and a half, as did their debut single, "Ain't 2 Proud 2 Beg." Tonight they perform at Capital Centre with Bobby Brown, Mary J. Blige and Shabba Ranks.

TLC's quick rise is hardly surprising to anyone who has heard the group's catchy singles on the radio -- "Ain't 2 Proud" was followed into the Top 10 by "Baby Baby Baby" and "What About Your Friends" -- or to anyone who has seen the videos that showcase the trio in baggy, psychedelic fashions, sometimes accessorized by, er, condoms. Left Eye has even been known to wear one as an eye patch (over her right eye, naturally).

That's not just a fashion statement, but a social one, a radio- and television-friendly public service announcement that sex is to be enjoyed, but safely. Still, TLC's live television debut was briefly delayed when Fox's "In Living Color" blanched at the wearing of condoms and at some of the lyrics in "Ain't 2 Proud 2 Beg" (this from a show that doubles entendres in its sleep).

Safe sex, says Left Eye (born Lisa Lopes), "is one of the most serious issues today and one that needs to be taken more seriously. Too many kids think condoms are nasty and vulgar, instead of as something that can save your life. ... Protection is a priority and this demystifies it. The reality is that people are having sex, and since they are, they should be safe."

TLC's sound has already been dubbed New Jill Swing, which both amuses and annoys the trio. "I don't know what they mean by that," says Left Eye. "I know New Jack Swing is a style that Teddy Riley brought out {with Bobby Brown}. They also call us the female Bell Biv Devoe, or another Salt 'n' Pepa, but to me we're on to some other stuff ... funk, rap and R&B."

And, she adds during a recent Washington stopover, "this is funky {pointing to Chilli}, I'm kick-ass, and that's voice {pointing to T-Boz}. It's one but three!"

And altogether it weighs less than Joe Jacoby. All three women stand about five feet and carry appropriate poundage and still look so young it's easy to forget they're in their early twenties. "Everybody thinks we're teenagers," complains T-Boz.

Left Eye is from Philadelphia, T-Boz (Tionne Watkins) from Des Moines and Chilli (Rozonda Thomas) from Atlanta, which is where the talent show veterans met late last year. Left Eye, the rapper in the group, and T-Boz, the sultry voice, were already working together but a third party didn't work out: Enter Chilli, then working as a dancer with rapper Damian Dane.

Drawn to Atlanta, which looks to be the music city of the '90s, the three had auditioned for the veteran singer Pebbles, who obviously liked what she saw and heard and signed on as TLC's manager. That's also when they first picked up their nicknames: Lopes became Left Eye after a come-on from a guy who insisted that was his point of fascination. Watkins became T-Boz for Tionne and The Boss.

"Then I had to get a nickname so that it all fits better together," says Thomas. "And Chilli fits me because I'm kind of Miss Hot Mama." (The other women giggle at this.)

Coincidentally, Pebbles's husband, Antonio "L.A." Reid, is one of black music's hottest producers and head of LaFace Records (with production partner Kenny "Babyface" Edmonds). Both did some production work on "Oooooooh ... On the TLC Tip," which also features other hot producers Dallas Austin (Boyz II Men, ABC), Jermaine Dupri (Kris Kross) and Marley Marl (L.L. Cool J).

"Each of them did what they do best on the album," says T-Boz. "Marley Marl is a rap producer, so he did the rap cuts and brought out our best abilities. L.A. and Face, they're very good with ballads, though 'Shock Dat Monkey' {a song about keeping misbehaving men in line} is fast and it's a pretty cool song. Jermaine is street {sound}, and Dallas Austin, he calls what he does new era revolutionary street music."

TLC did expand on the New Jack Swing formula, mixing and matching melody and rap without ever allowing one to intrude on the other.

"It's like three different artists together," says Chilli. "You would never see me doing Left Eye's part, or T-Boz's. And they would never do my part. That's the difference between us and harmony groups like Boyz II Men and En Vogue -- they have to depend on each other to make that complete sound. We don't. It's like here I am, there she is and there she is... ."

"And that's what makes us so unique," says Left Eye. "We do have a funky deep low voice, and totally opposite to that in contrast we have Chilli's voice, which is higher and more R&Bish, and then me, the rapper."

It's a complete package of style, dance and music, all underscored with a sassy attitude that often finds deeper levels, as with "His Story," which is about women whose allegations of harassment are too easily discredited by the men they accuse. When it does school programs, TLC changes "Ain't 2 Proud 2 Beg" to "Ain't 2 Proud 2 Stay in School," aware that its success has made its members role models.

"It's something we take advantage of because it allows us to talk about things like safe sex and abusive relationships," says Chilli. "I wouldn't exactly call us feminists because a feminist is a woman who just looks out for the women, period. We look out for whatever we think is right, whether it's a woman or a man. It just so happens that we are women and know things from a woman's point of view. We don't always know what a man is thinking."

And while they usually know exactly what a man is thinking -- and through their music they respond on their own terms, describing how they expect to be treated in bed and appreciating a good lover -- TLC members also celebrate their independence. "I got to be feeling free and you better believe I'll do what pleases me," they sing at one point, adding, "I can depend on myself, I don't need anybody else to be on my back like that." They insist on their rights to dress as they please, date whom they please -- or be alone if they please.

"The truth is, women don't stand up, they're too hushed, they don't like to say stuff," says Left Eye of the equal opportunity sex talk in "Baby Baby Baby" and "Ain't 2 Proud 2 Beg" (with its chorus dismissing the importance of the size of a man's sexual organ).

"If a man says it, it's good, but if a woman says it, it's bad. But all 'Ain't 2 Proud 2 Beg' is about is not being too proud to beg for something to call your own, and that's your husband. If you are married, you're not going to care if {he's well endowed}, you love your husband and that's the truth. It's about being real. It's not about going out saying, 'Hey baby, let's have sex.' "

Even their fashion stance isn't happenstance: TLC's clothes may be as loose and baggy as En Vogue's are skintight, but there's no moralizing involved. "We're not telling people to dress like we dress, or that wearing tight clothes is wrong," says Chilli. "We're saying that you should be comfortable and you don't have to have your breasts or butt out to get a man or to make it in the business. You can be just as sexy in guy clothes as you can in a dress. Just be comfortable."

In any event, it's a winning image and, says Left Eye, "We did want to stand for something, not just cute girls with cute concepts. Everything we talk about has meaning behind it. We didn't know we might become role models but it's good that we did because if you're put in a position like this, you should try to make a difference because a lot of kids today don't have role models. Some don't even have parents to look up to, so if they have something positive, it can make a difference in their lives, even if it's one life. And you never know whose life you'll change -- it could be the next president!"

Certainly, their lives have changed since the album's release -- their first tour was opening for Hammer and Boyz II Men -- but their feet still seem to be solidly on the ground.

"It surprised us," Left Eye admits. "And we don't take this for granted because we know what kind of position we're in. We're not stupid to the fact that you can't just be a group and hit it slam and be big in a matter of five or six months. We know that's a fairy tale and we happen to be living in it. For us to say, 'Oh, yeah, we deserve it' -- it could be gone tomorrow. And we'd be sorry, so we try to make the best of it. ... We want to take advantage of what we have."

And so do some of the fellas, apparently. They laugh about men hitting on them as they toured the country with Hammer and Boyz II Men.

"They're trying to test us," says Chilli. "They think all this TLC stuff is a gimmick, but when we sit up there and be like that for real and don't take no mess, it's okay. We're the fresh meat of the industry and it's funny to sit back and watch what guys'll do to get at you. You can see right through them."

And, if need be, they can always turn to one of their own lyrics if things get out of hand: "My knee correct dat effect."