2 Part Technique - As soon as you are mounted, immediately turn and face the leg that stepped over you because it will be considerably lighter and therefore easier to manipulate during your escape. Don't turn too far onto your side; exposing your back to your opponent's chest will make it difficult to return back if he imposes his weight. Press his leg into your half guard, and quickly turn onto your opposite shoulder so you can press on his other leg and hip escape back to full guard. To defend against the crossface, contour your head and shoulders a so his attempts to turn you back just brush off. If he does manage to snag an edge of your face or neck, use your bottom hand to free the pressure from your head and use your outside leg to trap his over his calf. With both posts on that side captured, bridge continuously over onto your knees and posture inside his guard.