Your Sister's Sister (2011)

Your Sister's Sister (2011) is about a few friends who have a weekend getaway on an island after the death of a friend's brother. She invites the mourning friend and he ends up being tempted by his friend's sister. Rosemarie DeWitt plays the super sexy temptress who Mark Duplass accidentally spies wearing no pants! Whoops! It works out okay because the pair end up having sex in another scene on a too-small twin bed. We have the hots for Your Sister's Sister, too!