A soda can. I used one once with friends on a holiday since we wanted to get stoned, had a small amount of herb, but not enough for a joint, and nobody had a small pipe or one hitter.
I tried vaping from a MFLB years ago when it was pretty new. It worked very well and I was surprised at how high I got from one or two tiny hits of vapor. The high was psychedelic and sort of like eating cannabis but without the confusion, body load, or pure mindfuck and completely psychedelic experience that happens when you eat a large dose of cannabis or hash.