"Hey Steve, that fish shirt your wearing is pretty sweet. You should wear it everyday."
"Thanks Tage, I know. I love it and I am tempted to wear it everyday."
"No Steve, that shirt sucks. I was just kidding."
"Obviously, DOUBLE BLUFF"
If a bunch of college guys pull a prank on some girls by staging a fake robbery in a house and the house actually gets robbed while they are joking about it being robbed. It would be a double bluff.