facebook twin
When your sibling adds someone on Facebook who has the same birthday as you, and then you both realize you're twins. Probably because you both have bad luck.
My brother added a guy with the same birthday as me. We both screamed, 'Are we twins? Are we really twins?'
My sister added a guy and said, 'He’s my twin!' I said, 'He’s my twin too! Now we’re all twins!'
My brother added my Facebook twin and I yelled, 'He’s my twin! Now you’re both losers!'