For me that experience was only positive and interesting. No feeling of being trapped, nor any lucidity or other kind of awareness for that matter. I can best describe the passing of time as both similar and dissimilar to the common experience with marijuana where time becomes intangible and just runs off - e.g. going to the toilet and coming back 20 minutes later asking everyone how long you were in there. There was no sense of waiting or idling, but instead distinct memories that amount to time. The largest feeling was that of exhaustion when coming out of it, akin to collapsing in bed after an incredibly long day, but that wore off quickly.