window dresser
A person, more often than not a female, who dresses slighty slutty, flirts with guys so she can get free drinks, then leaves them with blue balls at the end of the night. This is much like a manequin wearing designer clothing in a store window. You can look at it through the window all you want, but you can never touch it.
"Andy" was hitting it off with "Karla" all night at the local watering hole. She looked fine and seemed so into him, and he even bought her drinks all night. She hinted that they might go back to her place at the end of the night, so he kept buying her drinks. Then she told him she was going to the bathroom and he never saw her again. What a window dresser!