Yes, knocking ash off of a cigar is an acceptable practice in cigar lounges. Knocking the ash off of a cigar helps keep the smoke from becoming too hot and preserves the flavor of the cigar. This can be done by tapping the end of the cigar gently on an ashtray or other hard surface. If using an ashtray, make sure to hold it away from you so that any ashes that fall do not land on your clothing or furniture. Avoid shaking out excess ashes as this may cause them to scatter and become disruptive for other patrons in the lounge.