A great visual explanation of how to administer an epi-pen to someone experiencing severe anaphylaxis as a result of a food allergy, bee sting, etc. Plus commentary from Tumblr.
I’ll add: Absolutely don’t be squeamish if someone needs you to do this for them. Once I accidentally bounced the epi-pen off my leg when I jabbed myself with it during a severe reaction. You need to jab and hold it. Basically none of the medicine actually went in. Fortunately I carry a two-pack and was able to use the second injector, and I’m still around to tell the story.