After the previous incident, we got along very good and close too each other as a professor and a student. she was very always curious about our nudist lifestyle.

One day, she asked if she could visit our home and observe our lifestyle. We agreed, and she came over to our house. She was fascinated by our nudity and asked if she could watch us having sex. We were a bit surprised, but we agreed.

The professor watched as my sister and I started making out. Our bodies were entwined, and our hands were exploring each other's bodies. We were both getting turned on, and our professor was watching intently.

My sister then started sucking on my dick, and I could feel her lips wrapped around it. She was sucking it with such enthusiasm, and I could feel myself getting closer to cumming. The professor was watching us with a mixture of fascination and desire.

I then decided to return the favor and started eating out my sister's pussy. She was moaning with pleasure, and I could feel her getting closer to cumming. The professor was watching us with a look of pure desire on her face.

I then started fucking my sister, and she was moaning with pleasure. I could feel her pussy getting tighter and tighter, and I knew she was about to cum. I then pulled out and shot my load all over her stomach and tits.

The professor was watching us with a look of pure desire on her face. She then asked if she could join in. We both agreed, and she started sucking on my dick. It felt so good, and I could feel myself getting hard again.

My sister then started eating out the professor's pussy, and she was moaning with pleasure. I then started fucking the professor, and she was moaning with pleasure. I could feel her pussy getting tighter and tighter, and I knew she was about to cum.

I then pulled out and shot my load all over her stomach and tits. My sister then started licking my cum off the professor's stomach and tits. It was such a hot sight, and I could feel myself getting hard again.

We then all collapsed on the bed, exhausted but satisfied. The professor then asked if she could visit us again. We agreed, and she left our house with a smile on her face.

From that day on, the professor became a frequent visitor to our house. We got her introduced to Mom and elder sister as well. It's been few weeks, mom and my professor have been close friends since then.