Sure, everyone appreciates a humorous bumper sticker - except, possibly, the next owner of your vehicle. Many drivers opt to customize their car with pictures, sayings or political messages, but if you plan on selling your car, these could ultimately hurt the resale value, even if only by a bit. That's why many instead choose window decals.
Decals help drivers customize their vehicle just as well as bumper stickers, but they hold a key advantage - they're easily removable. Putting decals on your vehicle is not rocket science, but it is a bit more complicated than simply slapping a sticker on.
First, identify where the decal is going. Depending on whether or not the image is reversed, it may be made for the exterior or interior of a vehicle. Clean off the area to which the decal will be affixed with a cloth. Peel a small part of the backing off and push that part firmly onto the window.
Then, fold the decal down, slowly pulling away the backing and attaching the decal as you go. Now all that's left is dealing with the air bubbles, which often pop up with big stickers like this. One strategy is to use a credit card to smooth out the air bubbles as you go. If some persist after you've attached the decal, you can use a small pin to pop them open.