Friends With Benefits (2011) -

Dylan (Justin Timberlake) and Jamie (Mila Kunis) are watching a movie. Jamie says she misses sex. When she gets down to pick up the rubbish from their meal, Dylan looks at her butt. He suggests to her a relationship without the complications of it. Realizing they are attracted to each other, they conclude that this idea could work. Jamie makes Dylan swear that it will never be more than sex and that whatever happens, they will remain friends.