Creative What Not.
I only ever slept with your grandmother.
This postcard is from the Granpa in Little Miss Sunshine to Dwayne.
In the film he tells Dwayne to sleep with as many women as possible, but in (this) reality (that I made up) he has only slept with his grandma.
He misses and loved her so much that he tells Dwayne to be promiscuous so he won't go through the same pain.