phantom bumming is when you take a picture of a friend stood right behind someone else who is bending over although the person who is bending over shouldn't be aware of this occuring when you look at he picture it should look like your friend is making love to their bottoms.
i got an imense phantom bum at the co-op.
i dare you to phantom bum that old lady.
i hope i didn't just get phantom bummed when i picked that up.
i bet i can phantom bum your mum.