Fitting Bikes in the back seat

Ok, I'm going on my biking trip right now, and well, I'm learning very hard, the back seat isn't fitting my bike.. Just barely, and almost bent my door from pushing hard on it to close it (i didn't realize it was so hollow)..

How can I fit my bike in properly? It's a full size bike. Thanks...

Get a trailer hitch installed. They have a bike rack that goes in the opening for the trailer hitch. Use it and remove it when you get back.
Otherwise remove the front tire and install when you get their.

Take both wheels off and you can probably fit the bike in the trunk and close it also. I used to do this all the time in cars smaller than yours.
If you just remove the front wheel the bike should fit in the back seat.
Quick release wheels make quick work of this.
Have fun on your bike trip.