Well, ok. It wouldn't be a bad ide to learn the names of the muscles involved, btw, but i guess this is not the important issue...

What you have been doing is develop your biceps. Part of it anyway. I am assuming your palm is facing upwards. Try the same exercise with the palm facing down, and you should feel the burn (I've always wanted to say it) in your forearm and wrist muscles.

For more forearm development try something that climbers do: get 5-6 rubber bands, put the tips of your fingers together in a pear shape and put the rubber bands around them. Now open your fingers as many times as you want.

For the "wings" or latissimus dorsi or dorsal, do pullups. Once pullups are too easy attach 15 kg to your waist and go at it again. There is no better exercise.