Joking aside, what I did growing up (perhaps it is based on local customs) is: no genuflecting beforehand if it is normal communion formation at chapel Mass, walk up, kneel directly, receive with eyes closed, make the sign of the cross after the priest moves away. Don't chew the host. Dont hold it in your mouth any longer than you need to. If you must cross the center immediately after receiving, you dont need to genuflect. Our Lord is in you physically and spiritually. Similarly, the priest doesnt genuflect to the tabernacle as he distributes. He carries Our Lord with him. After 20 mins or so, the physical presence is gone (spiritual presence remains). The tabernacle closes, and you again genuflect any time you pass in front or enter the chapel (or step in or out of the sanctuary if you are sacristan or server).