Okay, for Carla you need at least 4 affection points on that day and you must've seen her masturbating with a dildo beforehand. The dildo scene is 4 days prior, right after Jasmine finds you in the locker rooms. To get it, you need 2 affection points with Carla at that time and remain quiet when you come back home.
You're about 30% done with the game but if you're considering to start fresh, I'd recommend you a mod I made which mitigates these kind of headaches.