The is part of a combo-chain of phrases used to express increasing levels of excitement or emphasis.
Firstly the OM(F)G, and then usually (and interchangeably) WTF and/or BBQ.
Including BBQ/WTF after an OM(F)G is often a sign of sarcasm.
"OMFGBBQ I just won the lotto!" (sincere)
"OMFGWTFBBQ you're the coolest person ever!" (mocking)
The Urban Dictionary Mug
One side has the word, one side has the definition. Microwave and dishwasher safe. Lotsa space for your liquids.
Buy the mug