well, if you are sure (not just hearsay) that he will blackmail you with it, then i say get to him first. whip up a quick bingus out of a bottle, etc, and burn the tiniest little bit of nug in there, then stash it in his room and run to mom.

if he's not blackmailing you though, listen to what the others said, he's just trying to look out for you from his skewed perspective.