Bro: "Um.. thanks.."
*hot girl walks by*
Male Cashier: "Oh hey look, the college girls are back in town. Looks like some fine ass scenery!"
The Male Cashier realized that he sounded a bit too interested in the bro's fashion choice. He brought out his straight cred to fix this critical error.
Jim: Hey, look at that hot chick riding in the back of that sausage wagon!
Tony: Yeah, that's their straight cred.
Dax begrudgingly brought his girlfriend with him to the lake as straight cred. He knew what a bunch of dudes in a giant boat shaped like a penis would look like to onlookers.