From the mailbag . . . .

DEAR BOB: "I am a 26-year-old legal secretary in downtown Washington. Even though I don't make a whole lot of money, I am very careful about the way I dress. I usually wear suits, or matching tops and skirts. I'm never sloppy and never tacky, and I never wear too much makeup.

"Last week, one of the senior partners (a man, of course) called me into his office and told me I would have to start dressing differently. I asked him what he meant by differently. 'More elegantly,' he said. 'A lot of the attorneys think you're dressing too casually.'

"Bob, I'd love to dress more elegantly, but that's tough to do on $19,500 a year. It sounds to me as if they really want me to quit. What do you think? What should I do?" (SIGNED -- Litigious Louisa).

DEAR LOUISA: I have two answers for you. One applies if you want to be litigious, and are prepared not to work at the firm any more. The other applies if you want to mend fences.

First approach: Ask to see the senior partner again. Tell him you'd like him to be more specific about how he'd like you to dress. As soon as he has finished, write up a memo of everything he just said. Then consult an attorney (no, not one in the firm where you now work). You may have a sex discrimination case. After all, they'd never tell a man to change the kinds of ties he wears, would they?

Second approach: Ask to see the senior partner again. Lay it on thick. Tell him you never intended to embarrass the organization, or him. Tell him that it takes a true friend like him to open one's eyes to one's sartorial sins. Tell him it'll never happen again. Then go out and buy a few $15 blouses. The guy will think you've gone for elegance, when you will only have gone for newness.

DEAR BOB: "My son is driving me out of my mind. He is 14 years old, and he refuses to lace up or tie his sneakers. When he walks, his foot squishes from side to side. Not only does he look like a total slob, but I'm afraid he'll sprain his ankle. He tells me to cool it because all the kids do it. I ask him whether he'd jump off a cliff just because all the kids do it. He tells me that's an inappropriate analogy. Can I give him your word that he's doing something dangerous? He reads your column every day." (SIGNED -- Rosalyn from Rockville).

DEAR ROSALYN: Don't take my word. Take the word of the three local orthopedists I consulted. Each says the last two years have brought forth more "cheap" ankle sprains, pulls, twists or breaks than at any other time in his career. And each orthopedist blames untied laces.

I think time will heal this one, Rosalyn. After all, fads disappear, by definition.

But you might try the old shockeroo technique. Take the kid to an orthopedist's waiting room. But don't just show up. Without telling your son, plan the visit for a time when the receptionist tells you that several bum-ankled teen-agers will be sitting there. Maybe your kid will take the hint.

DEAR BOB: "I am writing to you because I just don't know where else to turn.

"I am a 25-year-old woman who works in an office on Capitol Hill. I am quite attractive, if I do say so myself, and I get an awful lot of requests for dates. I turn most of them down, either because I have too much work to do, or because the men just don't interest me.

"Over the last few weeks, a very attractive man who works for another Congressman has begun striking up conversations with me. I have never felt my heart go pitter-pat before when a man walks into a room, but my heart is working overtime on this guy. He is tall, dark, handsome and hunky.

"For the first few weeks, the guy didn't ask me out. He just talked to me about Iran-Contra, Biden and all the other wonderful stuff that's been going on up here. Then he asked me to go to dinner. I was delighted!

"But then he put me off so totally that I refused to go. He said he'd take me to dinner only if I showed him a card certifying that I had taken a blood test and was free of the AIDS virus.

"I said I hadn't taken any such test and had no plans to. I also said I didn't see why I needed to be AIDS-free to eat dinner with someone. He insisted. So I said no.

"Now I'm wondering if I made a mistake. Not many people are as hunky as this guy. Could I have blown my big chance? (SIGNED -- Ruth Ann in Rayburn)"

DEAR RUTH ANN: I've heard of AIDS paranoia, but this is ridiculous. The guy may be a hunk, but it sounds as if his brain is a hunk, too. A hunk of lead.

If you care to pursue this -- and my advice would be, don't waste your time -- point out to the hunk that he is not just asking you out to dinner. By demanding that you take an AIDS test, he is simultaneously inviting you to certain festivities that may follow dinner.

Tell him that, on the planet you inhabit, one step follows another, all in good time, and you're not going to worry about crossing home plate before you've gotten to first base.