What do I need to say in spanish to negotiate BBBJ CIM?

it's a lot tougher to get a BBBJ in TJ. Not impossible but not that easy to get. Remember that many of the street girls are HIGH volume.
The club girls can be high volume too so a BBBJ is more a rarity than the rule.

check your personal message for what you're looking for

BB anything in TJ.  Probably a good thing because of the volume and sketchy sanitation.  Streetgirl-wise, you're asking for trouble.

Deseo sexo oral sin condon = I want a bbbj.
Deseo terminar en la boca = I want to cum in your mouth.

It's possible, but somewhat difficult, to get a bbb4j; a bbbj-cim is harder.  Ask, and offer extra.

The best bet is with an escort agency, like Team Juanita.  Be sure to specify exactly what you want when booking the appointment.