Lindsay and Sam Squabbling in Sin City?

Wonderwall, Thursday, March 12, 2009, 11:54am (PDT)

By Kat Giantis

Lindsay Lohan and Samantha Ronson seem to have just two settings for their relationship: drama and discord. And the switch was flipped on both in the wee hours of Tuesday morning in Las Vegas, where the spat-happy squeezes supposedly had yet another dust-up during Ronson's DJ gig at hot spot Prive.

"Lindsay decided she was going to surprise Sam at the club and showed up around 1 a.m.," a source tells the London Sun. "Sam appeared to be furious and the two started to argue in the DJ booth, before Lindsay began dancing wildly."

Around 3:00 a.m., Ronson was spotted hopping into her Porsche at the valet stand and driving off into the night. Lohan turned up minutes later, with paparazzi conveniently on hand to capture her reaction when she realized she'd been left behind.

"Did she leave?" an increasingly distraught LiLo is heard asking. "Did she [bleeping] leave?"

TMZ.com adds that she impolitely demanded that security find her "[bleeping] keys, now!"

Lohan then purportedly climbed into her Mercedes and zoomed off.

"Everyone is urging Lindsay to leave her," a mole tells FOXNews.com. "They have the worst fights almost every day, but it's always Lindsay that does the crawling."

On the plus side, several items from Lohan's surprisingly successful leggings line come with kneepads, thereby reducing the physical -- if not emotional -- toll of her alleged post-tiff penitence.

Speaking of her business ventures, Lindsay has been out this week plugging her soon-to-debut spray-tanner, Sevin Nyne, a name she says she chose because the numbers are meaningful to her, and not, as we hoped, because she's a really big fan of Jeri Ryan's work as Seven of Nine on "Star Trek: Voyager."

"As much as I love the sun, it is so bad for your skin," Lindsay explains to People. "I have tried every product on the market and never found something that I loved."

The thrice-rehabbed starlet, whose own skin tone is typically a hue that falls somewhere between mashed yam and traffic cone, is most excited about her new product's nourishing ingredients.

"It was important to me to have a natural product that didn't have a lot of dyes and chemicals," she peddles. "Our product has goji berry extract, which has antioxidant properties. It has a natural golden color. It doesn't streak and smells delicious -- not like a typical tanning product."

The spray, which shouldn't be confused with an insecticide that's also named Sevin, will retail for $35 and can be purchased only at Sephora starting May 1, although if you're desperate to show off a healthy glow come tax time, you can get it on the store's website starting April 15.