Marcelo explains the subtle, yet critical aspect of keeping track of your elbows in relation to your upper body when defending against and opponent's under-hooks and/or recovering from bottom position: Keep your elbows tight against your ribcage to prevent your opponent from invading your armpits or triceps with under-hooks and even over-hooks. If your opponent is close and trying to solidify top position with chest-to-chest pressure, never extend your arms away; otherwise, you run the risk of getting caught in a submission-hold. Utilize quick bursts and small short bumps of bridging escape attempts until you can safely find an opening to recover your guard and escape your hips away, or turn over onto your knees with under-hook of your own and possibly a single-leg attack.