No shiva is not on drugs, and although in the form of Rudra and bhairavar he is depicted as being angry this is really just an expression of his power for destroying demons/asura's. Lord Shiva is a loving God who cares for his devotees like a mother because he is inseprable to his shakti-energy which is Parvathi. Shiva will never be angry at his devotees and will only love them and bring them on the right path. I have not heard of people offering him opium but I know that in some places in northern India he is offered cannibis. Although all mainstream Guru's, Priests, and Devotees believe intoxicating substances are harmful (this is why most hindus dont drink) there are many Sadhus who smoke cannibis daily and being devotees of shiva offer it to him. No shiva doesn't need to have his anger cooled because he is the creator of the Universe even if he did have a temper offerings of opium wouldnt do the trick, these are just gestures of devotion which are meant to show love for the Father! Im posting a link to a beautiful free downloadable book that tells all about shiva and his attributes published by the creators of "hinduism today" magazine.