Aggressive or pushy in an attempt to get someone to do something. Likened to a door-to-door salesperson literally sticking their foot in the doorway so that the door cannot be closed. I was considering signing your petition, but your foot-in-the-door methods have made me change my mind.
Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.
If you describe a way of doing something as foot-in-the-door, you mean that it is done in an aggressive or forceful way, in order to persuade someone to agree to do something which they probably do not want to do. Double glazing salesmen have become a bit of a national joke, what with their foot-in-the-door methods. For many people, the image of the foot-in-the-door tabloid hack represents all that they find distasteful about the journalist's trade. Note: If someone manages to put their foot in a doorway, they can prevent another person from closing the door and keeping them out.
Collins COBUILD Idioms Dictionary, 3rd ed. © HarperCollins Publishers 2012
foot in the doorSlang
1. An initial point of or opportunity for entry.
2. A first step in working toward a goal.
American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.