'Bad Girls' Chick -- Shoppin' Her OTHER Sex Tape...!!!!

What do you do when one of your three-way sex tape partners blocks the sale of the flick? If you're "Bad Girls Club" hell-raiser Erica Langston ... you simply sell your OTHER sex tape. Duh.
Sources tell TMZ Langston and one member of the ménage à trois -- her boyfriend Adrian -- tried to sell their masterpiece to Vivid Entertainment head honcho Steve Hirsch earlier this week ... but sex tape partner numero tres threw a wrench in the deal.

We're told #3 -- who happens to be one of Langston's "BGC" castmates -- demanded way too much scratch for the tape ... around $200k ... so the deal went sour.

But our sources say Langston had an ace in the hole -- another sex tape with Adrian ... sans her financially demanding XXX cohort. 

We're told Hirsch made a new offer for the two-person porno ... and that the deal is all but sealed.