So this has happened before. But very very very rarely. I am giving digits to an SP. She is tight. Has great muscle control. Then suddenly, her pussy, inside, opens up. Becomes a huge vacuum inside. I could fit a golf ball or more in there. She is still responsive and seemingly enjoying the digits. Then she becomes tight again. What is this all about? It isn't common. Most women retain a more or less consistent tightness during digits. But every once in a while ... Wow