The night before last, former O.C. temptress Mischa Barton scooted into a London taxi, her dress slipping aside to let a bit of nip hang free.

And yesterday, nearly the same thing happened to the exact same boob!

Clad in a slightly more casual ensemble, Mischa forgot a bra yet again, and as she was flashing her stunning smile for cameras, her left Barton button leaped out of her dress.

Two nips . . that's nearly enough to make a mouthwatering Misch-kabob!

Be sure to check out the entire set of pics of Mischa semi naked at Less Clothes.