Step Sister and her friend fucked together

Step Brother liked his Step Sister's friend very much, he said to his Step Sister, make your friend my girlfriend, in return you will give what you say. Step Sister said I will make my friend your girlfriend but you have to have sex with both of us together because we both have a desire to do a threesome for a long time but are not able to find a boy, anyway, my stepbrother, the boy is ready, then the step sister calls her friend and all three have sex together.