Where do you inject a glycogen shot?

I heard someone tell a story the other day about her brother and sister that had diabetes and how her brother had a seizure one day because his blood sugar was too low. And she gave him a shot right around his heart to make it stop. At first I thought she was referring to glycogen, but I was told that needed to be injected in places like the thigh or upper arm like you would an epi-pen. So I was wondering is that a place you should inject glycogen or was she talking about something else entirely?