Lay on your back. Extend your straight arms above the chest and raise your bent knees till they are over your hips.
Lower opposite limbs towards the ground. You can feel the ground but do not rest on or tap off of the ground.
Maintain a flat lower back throughout the movement (lower back should be in contact with the ground).
Руководство по Упражнению Dead Bugs Cross Lateral - Тренировка Abdominals | MuscleWiki