BBBJ means bare back blow job, which means the provider gives oral service without having you use a condom.  CBJ means the provider have you use a condom when giving you oral service.  DATY means dining at the "Y", which means that you give the provider oral service by licking and playing with the genitals.
    If you want a complete listing of terms and more go to the post by MichaelCA (name highlighted in red) below on this page, there are plenty links to info and other stuff you may want to know there.