Holding cut buds in the mouth is pretty common practice. Sometimes smokers are advised not to do it. It is probably unlikely that human mouth microbes will infect plants. All the same I usually clean my teeth extra well when budding, dont eat during during work periods, and drink and rinse with plenty of water while budding. Touching the cut surface of buds is probably different. When budding your fingers are handling plant stems, pots etc etc. These are more a source of plant infection microbes than the human body??