Jennifer Aniston wanted to make 'We're the Millers' ''even crazier''.

The 44-year-old actress proposed the kissing scene in the American comedy, where she locks lips with virgin teenager Kenny (Will Pouter), in a bid to push the saucy script to its limits.

She told Total Film magazine: ''We wanted it [the script] to be pushed further. Like the scene where Emma Roberts' character (Casey Miller) is teaching Will Pouter's character to kiss. It was like, 'why not go even crazier? Have more fun and take it a step further.' So now the mum comes in and joins in.''

Aniston's instincts were proved right at the test screenings when the scene grabbed the audiences' attention.

Film director Rawson Thurber said: ''I wrote that in but didn't expect the reaction the audience has to that scene ... They lose their minds.''

Jason Sudeikis, who plays drug dealer David Clark, also made tweaks to the script to make it funnier.

Thurber explained: ''Jason was always able to bring three or four spins on any scene. His second takes would be so much funnier than anything I could have come up with.''

Aniston added: ''He's an amazing writer.''