If I understand you correctly, you want to smoke the tobacco left in the cigar butts that are too short to smoke safely as is?
Well, the tobaccos at the back end of a cigar are not really intended to be smoked, as they are used more as a filter. YOu can smoke them, but they are not the quality of tobacco used up in the first 1/2 to 2/3 of the length of a cigar. Why not put them in a jar, and when you have several butts saved, put water in the jar, and let the butts steep for a couple of days? Then you can pour this into your garden hose sprayer, and spray your plants, and the foundation of your house to get rid of the bugs, ants, roaches, and other creepy crawly things. The nicotine is a great insect repellant. If it rains, make some new soup with the butts, and spray again. I had a crabapple tree that had been damaged by storms, and carpenter ants were eating it to death. I stuffed my cigar buts into the main crack in the tree, and left there over the Fall and Winter, and Spring. When we were out cutting the lawn the next May, I checked the tree. No cigar Butts, or tobacco evident, No ants, and no sawdust residue. The tree began to heal itself that summer. Best darn insect repellant I have ever used. A chemist told me about this BTW.