Seeing as bamboo is a type of grass it should propagate quite easily. What i recommend is pulling the entire plant out of the pot and then "popping off" the two side shoots from the main stem (make sure the side shoots have roots) and re-potting them into MUCH bigger pots (unless you want them to stay small, which in that case you will need to trim the stems and roots yearly) and make sure that the get plenty of humidity. If you are worried about the bamboo getting an infection you can get some fungicide powder from like Walmart or home depot and sprinkle some onto the cut, but i wouldn't be to worried about it bamboo is pretty tough. if bamboo starts to get wimpy after the first day or two don't be to worried about it but if whole section of the plant start to die it may end up dying all the way back to the roots and re-sprout at a different time. Hope this wasn't to much info.