Horny older sister

His sister is 4 years older than him and was the girl who took his virginity. When he was 18 she just asked him if he still was a virgin, since that moment their relation changed. One day she got the courage to tell him she wanted to be her first. The first time was disaster, as expected but she insisted and things got really good. Now they have a very open relation and only have sex when they aren't in a relation with someone else, like in this video, fooling around in the bathroom while they're home alone.