Deep throat, deep french kiss, dine at the y

BBBJ = bare back blow job, i.e. felatio without using a condom.

DFK = deep French kissing, i.e. kissing with tongue.

DATY = dining at the Y, i.e. cunnilingus.

If you scroll over one page back, you will see a post from the moderator with a site giving a glossary of all the commonly used acronyms in the hobby.