Dressing windows at Barneys. Penning books. Helping deck the White House for Christmas. Fashion guru Simon Doonan seems to spread style everywhere — and to look thin and hip while doing it. His new book, “Gay Men Don’t Get Fat” ($25, Blue Rivers Press), details how to live a skinny, glam life. He’ll sign it at the W Washington (515 15th St. NW) Wednesday from 7- to 9 p.m. (free, but RSVP to whappenings@brandlinkdcrsvp.com).

This book suggests gay men are perfect. Is that possible?
We don’t have any flaws. We’re 100 percent perfect.

Is it getting easier to be out?
My generation, we had a lot of stuff to overcome. I came out when it was illegal to be gay. I think young gays today are approaching life with more optimism. I don’t know if they’ll be as creative as previous generations simply because a lot of creativity comes out of conflict and oppression. It’ll be interesting to see how many Alexander McQueens come out.

Aren’t gay men starting to take cues from straight-guy fashions, and vice versa?
I advocate gay men and straight men dress the same. There are basically three ways to dress. You can be a Perverse Prep, a bit Thom Browne and a bit Band of Outsiders. Or you can be a Heritage Henry, in all that rough work wear. Then there’s the douche bag look.

Looking like a douche bag is OK?
The “Jersey Shore” look? I don’t dress that way myself, but I love it. It’s flamboyant and fun.

Is it hard to be 50-plus and fashionable?
I don’t fuss about wrinkles and stuff like that. I’m a privileged survivor. My generation, we all thought we were going to die. Every birthday, I remember my friends who perished in the AIDS epidemic. I feel lucky to be happy, healthy and have a gorgeous boyfriend.

That’d be your husband, designer Jonathan Adler. How do you broker home decor decisions?
I defer to Jonny, because I don’t believe in doing things by committee. He’s got the creativity and products. When we first met, he moved into my apartment. Then bit by bit, he got into more categories of furniture and carpet. It seemed natural to have it in our house.

You guys seem so happy. Any advice to single guys and girls on how to find a mate?
Things happen when you let down your guard and you’re approaching it with fewer pre-conceived ideas. Girls and boys, if you’re looking for a man, just relax and sparkle, and something groovy will happen.

Is window dressing as important as it used to be?
Probably not. A 100 years ago, they were the primary method of customer outreach. Now there’s a million other ways to communicate.