On a way off note - next to Paris Hilton, Britney Spears looks really, really fat .

Anyway ...while maneuvering out of the cab in the black mini, Spears managed to flash her vag to the paparazzi .

Hilton has been Spears' partner in crime since the mom of two started on her freedom train around Las Vegas and Los Angeles after only two weeks of being single.

Last week, police were called to Hilton's home after the neighbors complained that Paris and Spears were blasting music too loudly and the paparazzi were getting out of control.

Page Six says after , Spears parted ways with Leslie Sloane Zelnik, she was using a publicity woman at her label, Jive Records - but she needs more help. "She is kind of a mess," said an insider. "She won't take anyone's advice."