Tell him to masturbate. Masturbation has always turned my bad highs into good ones . Or, you could just tell your friend to take only one or two hits? If he hasn't smoked in so long, then one or two hits will get him high, if it's good stuff.

If he has a bad high even then, then it would probably be better if he didn't smoke; obviously he isn't able to take it.

Secondly, if he does have a bad high, you just tell him to go jack off. Works for me! Looking at porn allows you to forget the paranoid thoughts and feelings. Actually, anything that can distract you from the paranoid thoughts is good.