You will.

"OK, Bob, I agree."

"But we need to make sure that no one is cheating." said Bob. "That no one is jerking before the challenge."

"And how will we do that?" asked you.

"I don't know... We can promise to play fair, you will cheat anyway."

"I'll not. But you will."

"Ha-ha! Oh! I know! We will look after each other. You'll stay at my place."

"Sounds fair."

The rest of the day you were playing video-games, watching movies. The awkwardness in that activity was that both of you checked each other's dick before and after going to toilet. You even left the bathroom door open to watch on Bob's arms.

So, it's sleep time. You've decided to sleep in one bed to listen each other. If someone jerk at night he will be double loser, that's what you've both agreed.