Weakly saying no isn't going to get you anywhere. It shows you have a weak sense of will. Agreeing to try it just once is still dangerous. And hanging around and making jokes about this decision still isn't going to get you out of the situation you're in. Suggesting an alternate activity might distract the person.
B. Suggest an alternative activity because no one will take u seriously saying no weakly and agreeing will be giving into peer pressure and hanging around if caught doing something wrong you will be a witness to it and also punished