Sticky Situation with parents and pot. PLEASE HELP?

So earlier tonight, my parents found a text message on my phone from my friend, asking whether i was going to bring him a weed brownie i made. the text also said how i smoked with him the other day. My parents got angry and found the brownie, then they questioned me about the part with me smoking with him, and i made the excuse that he wanted me to make the brownie for him, and bring it, and that the other day, i only stood watch for him, and that i've never smoked pot. however, i have smoked, and my parents are thinking about calling my friend's parents to tell them about it. Does anybody have any advice how to get them to not call his parents? I would feel really guilty if i got him caught. also, anything i could say to coax them into the fact that its normal for teenagers to be curious about marijuana? and no lectures please. i've learned my lesson