have two left feet
To be unable to dance gracefully; to have awkward or clumsy footwork while dancing. I've always had two left feet, so I was really nervous about our first dance after the wedding.
two left feet, have
Be clumsy, as in I'll never get the hang of this dance; I've got two left feet. This expression conjures up an image of feet that are not symmetrical, as left and right are, therefore causing imbalance or stumbling. It was first recorded in 1915.