On the floor...

You struggle to contain yourself as you ponder where to spray your load... In the end, you decide to play it safe... No need in doing something to get caught after all... You point your dick to the floor and begin to spray your load onto it, all the while caressing her breast...

Your orgasm is powerful as it tears through your body, culminating in a nice little puddle of semen at the side of your sisters bed...

You decide to cut out while you can and quickly put your cock away before slipping out of Sarah's room... Just for fun, you leave her uncovered, knowing she'll likely be confused about it but unable to say anything...