A submissive trainee's cocksucking skills are put to the test by their dominant mistress in a bi-threesome fantasy. The trainee, eager to please, takes both the mistress' strap-on and a hung bi-man, switching between them with increasing skill. The mistress, impressed, guides the trainee's head, pushing them deeper, making them gag and choke. The bi-man grunts in pleasure, fucking the trainee's throat. The mistress, satisfied with her apprentice's progress, rewards them with a facial, both men's cum dripping down their face.