Wait it out

You decide to just wait, and hope it goes away. Unfortunately, it stays, and when dinner end, it's still as hard as ever, and if anything, the tent looks bigger, and you've started breathing heavily.

"Can you move?" the girl asks, and you shake your head. "That's okay, I'll carry you."

Before you can say anything, she stands up, and lifts you into her arms. It's the classic pose, with one arm supporting your body, and the other arm supporting her legs, and it leaves your erection completely visible to anyone standing in front of her. It is even more visible to her, but she still seems not to have noticed.

Already, you notice one boy silently point it out to the boy next to him, and the pair are giggling. Now you might have to tell her. Your mind instantly spins some alternative options. You could ask her to carry you piggy back, you could hope that once people are all walking in the same direction, they won't notice anymore, you could ask those two guys for help. No matter what though, you get the feeling this is going to be a humiliating experience.