They reenter her mouth to pump cum, they want to impregnate her and think mouth fucking will do, (they dont know about human anatomy), The tentacles make long thrusts in and out of her body, continously pumping her cum into all holes on her body to impregnate her. The camera remains static and does not zoom in or change angle so it can film the entire sex act, from the cum coming from her mouth to the tentacles going into her body.