cigs for me ruin my high, if I smoke weed, I wont touch a cig for a good hour or so. I guess some people get higher with a cig and others just the opposite.

I think darkness would work, but also might make you tired to, which can give the feel of still being high?

I found these herbal pills at the local dietry store, Kanna, a mood enhancer. Take like 3 50mg pills and you'd sustain the hypnosis of marijuana. Just dont over do it, like 12-15 (no known over dose with Kanna).. cuz within 15 minutes you'll laugh, you'll cry, and you will feel so damn good.. but you wont feel the weed high much anymore.
more on Kanna here: http://www.erowid.org/plants/kanna/kanna.shtml