Stands for outstanding blow job. Given to a man because it was well deserved. Usually because he has done something spectacular. Also given until the recipient has achieved an orgasm. If bj's are given as part of foreplay, they usually aren't completed. Obj's are necessary every now and then.
Girlfriend: you are super sexual today!!! How about an Obj?!
Boyfriend: what about you?
Girlfriend: no, I'm fine. Giving you an obj would complete my life.
Loucy loves giving her boyfriend an obj on the reg.