Start thrusting brutally.
From Create Your Own Story
You allow primal instinct to take over and thrust deeply and powerfully into her mouth over and over again. Her nose smashes against your pelvis hard enough to make it bleed, but she doesn't seem to notice over the brutal facefuck you're giving her. A wet 'Gah!' sound escape from her throat every time you thrust in. She has enough time to breathe between thrusts that she doesn't pass out.