The full form of bbbj is bare backed blowjob
The definition of ‘bbbj’ is bare backed blowjob.
In simple terms it is the performance of oral sex on a man or blowjob when no condom is used, therefore bare backed.

Most often used when there might be someone listening to a conversation that you don’t want to know what has happened. The slang term is the best way to say something in a more confidential tone. While the abbreviation of bj has been an acronym for blow job for many years, the addition of bb quickly became just as popular.

Origin of BBBJ
Where this slang term originally began may not be commonly known, but the usage in social networking is probably the origin. College students began using the term to describe encounters or desires for encounters. But in social media this shortened way of speaking has seen a global explosion with countless instances of usage.

Conversation Examples
Texter 1: Did you hear about Jenny?
Texter 2: No, what now?
Texter 1: What she did with Ken…
Texter 2: What did she do?
Texter 1: BBBJ!
Texter 2: No way gross!