X17 XCLUSIVE - How It Went Down In The Car With Paris

Was Doug jealous of this???

Something went down in Paris' chauffeur-driven car Halloween night -- there was a struggle, some yelling, and then Paris' phone went out the window!

Fortunately for Queen P, X17 was there to retrieve her phone and when Nicky Hilton dialed the number later in the night, our guy answered and told her he wanted to deliver it to her, which he did.

So what was all the commotion about? And who was the guy jumping all over Paris and then walking arm-in-arm with her? Did Doug have his lingerie in a bunch over someone who's obviously just a friend?

Check out the video -- Paris is looking for her phone!