Best way to work out the outside of your peck

[Hitman821]

You can do this with thick telephone books on the floor and your legs elevated on a chair or something to train your pecs from a stretched position.
The guy in the video needs the third chair otherwise the exercise would be too easy.The higher the legs the harder it gets.http://www.youtube.com/watch?v=cqUg_gKNUT8

[mathed]

I would imagine that something like reverse side raises using a machine specifically made for that would work fine. Otherwise, wide grip bench or push ups should work too. Try to find those perfect pushups and start with your hand in the regular position and rotate them to the outside as you perform the pushup (so that your thumbs end up in the top vertical position), that should emphasize the underside of the arm and the outside of the pectoral near the armpit.

[TheNegation]

Wide Grip Bench
Wide Push-Ups
Cable Crossovers
Decline Bench
Paralell Dips

[Nosferatu]

dumbell flyes or any wide grip benching I also like dips with the elbows flared out and go deep