I re-light all the time. Set it down, let it go out.
When you want to re-light, pick up cigar, knock ash off, Purge (Blow through the cigar - opposite way you puff), then roast the end of the cigar until there is a glow all the war around the outside. Purge again for a full 3-5 seconds, then re-light.
Caveat Emptor - my taste buds are shot and I smoke Cain F for breakfast. Biggest takeaway - do what works for you. (I never use the plastic bag trick (or the snuffer) because I found the smell permeates the cigar - that one got to my taste buds!! )
