The more you can use your legs to pin and trap an opponents arms in dominant positions, the more you'll be entering into submissions. Pins are great for controlling opponents but that most of his defense when pins begins with his arms. If you can take of his arms out of by pinning it or trapping it, you will add greatly to the your pin presents to the opponent. So when you pin whether or chest to back, look to go the extra and pin/trap an as well and you'll be be able to do more than an opponent – you'll him!