I've seen vivid hallucinations just off of Salvia leaves smoked with a bong. The extract is a lot more powerful though, I think I just got a hold of some good leaves. Off of the leaves I had a couple of big trips that were pretty spiritual and enlightening and the few times I've done the extract it was more of a "trippy trip". But yeah, you just have to take a huge hit, as big as you possibly can, and hold it in as long as you can.