Sister’s friend came over and I was surprised by how sexy she was. Pretty blonde hair and a nice ass! My dick instantly got rock hard so I asked if she would suck it. That didn’t take much convincing but then my sister walks out and sees her brother fucking sister’s friend! She could not believe it so they went to her room. One thing leads to another and the two girls start having sex! I had no idea my sister was a lesbian! This is making for a good brother and sister sex fantasy! I walk in on them having sex and they invite me to join! I proceed to have them both suck my big hard dick and then I fuck them both good and long. My sister’s friend was loving doggystyle while she licks my sister’s vagina. Who said brother and sister sex couldn’t have a plus one? We all enjoyed the sex session and will definitely do it again!