The lid is almost open. Almost, but not quite.
When Sophia finally gives in to corruption, things will probably turn dirty way faster. She probably won't be able to get enough.
She has been developing quite a lot from some time know, she enjoys getting lewd eyes from her students when she exposes herself in the class, she likes to tease the guys, she felt really good from Tyler's attention in the club.
And now, she exposed her panties to Larry out of her own vollition because she was in a teasing mood and wanted to give him more. It's good that she don't need alcohol as an incentive anymore. Even if Larry scene wasn't the best mostly because of poor build up and writing, it was indeed a huge step towards the goal. (I still hate DeShaw's event and i will act as if it didn't exist, i will go as far as doing another playthrought just to stop any event with Vicky because of how awful this particular one was)