Tell him you'll be fine, you don't need to stop

"Oh no, I'm fine. I have to pee pretty badly, but I'll have no problem making it to your house."

Waylon looks back at you a bit skeptically.

"Uh huh. How much did you have to drink again?"

"Hey! I'm fully in control of myself," you tell him, socking his arm lightly.

As the two of you approach the lights of the gas station he stops and turns to you.

"OK, well, I have to pee so we're going to stop at the gas station anyway. You can wait out here or come in and use the bathroom."