https://www.slumi.com/
http://www.girlsbcn.com/
The above two sites are actually great as well , find the girl than copy/paste her number in to the search box on any page of the sexomercado site and her reviews will come up for you to cross reference , i use it in Madrid all the time ( Slumi ) ; Slumi is used everywhere in Spain and legit
Also, go to TER and see the girls other Americans have reviewed that also works and of course you can go on the ISG for great info .
If all else fails go to a walk in brothel , pick out of a lineup but tell the madam before the lineup you want only girls who offer " francés sin goma" and pay the girl the extra €10-€20 if need be but if u read the reviews you can easily find the bbbj girls most do and " hasta al final " are the ones who will suck you until you blow but 90% spit it out
http://www.devorahsuites.com/ is a slam dunk winner FYI and they have tons reviews on sexomercado but pay €100
Mike's photos you see posted are also an option if you like their looks look up their pages on sexomercado and not only will their reviews come up but so will the other girls they share the pisos with