[ Men's Health ] Open Question : Males doing jumping jacks in tighty whities and then naked: will this be super humiliating?

I'm a 25 year old male and I was out drinking a few nights ago, and after a few too many shots, I agreed to a stupid, drunken bet/challenge created by one of my friends. He wants me to do hundreds of jumping jacks back-to-back in nothing but my briefs (plain tighty whities) and my socks. After the 150th jumping jack I have to remove my briefs and socks too, and continue totally naked. He's serious about me doing this, and so are my other friends--if I fail, I have to pay $100 for losing the bet. How humiliating would most guys find such a bet? Am I going to have to do those jumping jacks with a massive involuntary erection from the friction of my penis rubbing against my briefs the whole time? Is there a chance that I'm going to ejaculate right in front of them? Sounds like hell, especially with four guys taunting me as they watch. I wonder if I'll ever be able to look them in the eye again, especially if I end up getting erect and ejaculating right in front of them. If you're a guy, would you do this, or just lose the $100 and keep your dignity?