Don't try this at home

WHAT DO Kim Kardashian, Paris Hilton, Rob Lowe, Tommy Lee, R. Kelly and Pamela Anderson - twice - have in common?

They all made private sex tapes that later became public.

This brings us to "Sex Tape," the romantic comedy starring Cameron Diaz and Jason Segel, which opens today.

Diaz and Segel play a married couple who make a sex video based on every position in The Joy of Sex. They upload it to the Cloud, then are horrified to learn it was sent to a handful of other iPads.

We dispatched romance columnists Steve and Mia to review the movie.

Steve: I'm always in favor of trying new stuff to bank the fires of a long-term romance. But replicating every position in The Joy of Sex? Remember our review of the updated edition just a few years ago?

Mia: Yes, I do. It was exhausting just looking at the pictures.

Steve: I'll say. With some of those positions, it should've been called The Agony of Sex. There was one that involved a phone book.

Mia: Where would you even find a phone book today?

Steve: Craigslist?

Mia: "Sex Tape" does make you think about the impact that long-term marriage can have on a couple's sex life.

Steve: Especially if you're a working couple with kids. Hell, you have to make a sex appointment two months in advance.

Mia: So, what are you supposed to do when you hit a sexual dry spell? I can see why Jay and Annie (Segel and Diaz) decided to make a sex video. What's hotter than seeing yourself and your lover going at it? Steve, have you seen yourself in action?

Steve: God, no! Seeing me having sex would turn anyone off sex forever, including myself. Seeing Diaz have sex, on the other hand, puts the Joy in The Joy of Sex.

Mia: Yeah, well I saw more of Diaz's butt crack during that movie than I ever thought I'd see.

Steve: We should tell our readers that the movie is really more of a chase movie than a sex movie, although you do get to see Cameron in bikini panties and roller skates.

Mia: And Jason in jockeys.

Steve: Back in '05 we reviewed "In Her Shoes," another romcom starring Diaz. We loved it, but she was a hot 32-year-old woman then. Now she's um, more "mature." Do you think she's lost some sex appeal?

Mia: Not a bit! She's still smoking.

Steve: There seemed to be a range of horror on how much embarrassment the couple would suffer, depending on who viewed the tape. What would be your worst case? If your mom saw it?

Mia: The worst thing isn't if anyone saw it. What would hurt me more is if my butt looked ginormous or if I had bacne or something else ratchet going on.

Steve: Good point. It's not who sees it, it's what it looks like.

Mia: Trust me. There are certain angles you might not want to see your naked backside from.

Steve: In my case, that would be any angle. I guess for couples crazy enough to do it on camera, though, we should offer some advice. What do you think?

Mia: Before you pull out the camera, there should be ground rules. I recommend making only one copy of yourselves in action. If you're tech-challenged, don't even think of uploading it anywhere. Instead, get an old-style video recorder that uses an actual tape that you can destroy yourself.

Steve: Yeah, you can buy those online. In fact, you can probably buy lost sex tapes online.

Mia: The couple should decide ahead of time who gets possession of the tape. Better yet, watch it a few times and destroy the evidence. Relationships can be dicey, and the last thing you want is to end up on a revenge-porn website.

Steve: Revenge-porn websites? Such things exist? You've given me a homework assignment.

Mia: You might want to leave your faces out of it and just show your bodies. Also, think about wearing a wig in a different hair color for a change of pace. Or maybe a Mardi Gras mask to conceal your identity. And don't forget lighting. You don't want it to be too dark while you're filming.

Steve: Hmmm. I'm looking at you differently. On your next shoot, let me know if you need a gaffer.

Mia: All I'm saying is, if you're going to do it, do it right. Make sure your room is clean. You want nice sheets on the bed. You don't want an ironing board set up in the background - unless you're doing a sexy laundress scenario.

Steve: Scenario?

Mia: Yeah, you need to set the scene. Have some sort of plot lines so you know which way you're going. In the movie, the couple made their way through The Joy of Sex. I suggest a pizza delivery-man theme.

You know, ladies, have your guy ring the door bell and walk into the house carrying an empty pizza box.

Steve: I'd rather have a guy ring my door bell and walk into my house carrying Cameron Diaz.