Used to express extreme surprise. Meaning, Oh my fucking god BBQ. The BBQ is added at the end to lengthen the acronym and make the statement more meaningful.
The awkward moment when you're watching a movie with your rents and a quiet graphicmsex scene come on. You automatically sink into your chair, blush and hope to god your parents dont say anything... In most cases you find a stupid excuse to leave room.
*Watching a great movie then suddenly a sex scene appears whilst your rent are in the room*
*you say under your breath omfgasexscene -.- while pulling an awkward face*' -.- '