My mates step-sister is very slutty

I saw my neighbours sister and told him she was cute. 5 mins later he's at my door with his sister. she walks right past me into the living room. all my buddy says is she's very open sexually then left laughing. i went to the living room and she had all her clothes off and let me tape it. we have sex all the time and post are movies and pics. she's nothing special but is open to anything.