Side control provides unique submission opportunities not available from other positions. Mastering the finishing mechanics of each creates a complete top game.
Drive their wrist to the mat at 90 degrees from their body. The angle determines the submission — too parallel and it's just an arm pin, not a submission.
Simultaneously raise their elbow while keeping the wrist pinned. Think "windshield wiper" motion. Never lose wrist contact or the lock loses tension.
Drive their hand toward their shoulder blade while stepping over their head. Prevent them from rolling by pressing your hip into their shoulder.
When they roll to escape, follow into belly-down kimura. This creates a different angle that's even tighter and prevents common defenses.
From side control, slide around their head to north-south position. Under-hook their far arm, drop your near-side arm under their neck, then squeeze your shoulder into their carotid.
From kesa gatame or side control with head control: cup both hands behind their head, drive your knee under their neck. Legal in no-gi competition at higher belts. Primarily used as a setup to open their guard or force reactions.