Aww man I thought id just stumbled across a good one but it ends up being a failed attempt in the end. Little Birds from 2011 with Juno Temple. She's been luring guys on the pretence of sex to abandoned buildings where her friends lay in wait to rob them. Right at the end of the film they try it on this guy that ends up being a Fucking Nutter. He smashes the fuck out of all the lads and they run off leaving her behind. He gets her bent over, pulls her shorts down, spits on his hand and lubes her up. He's just taking out his cock when her friend comes back and shoots him. What a Bastard. So Close!
https://www.imdb.com/title/tt1623745/?ref_=fn_al_tt_1