What is the meaning of the following term?

You are my bus movie when I am riding the blunder bus.

From the urban dictionary:

blunder bus :A blunder bus is where you masturbate. Taking a ride on the blunder bus is masturbating, and a Bus Movie is someone attractive that you think about while doing so.
That girl is real bus movie material, I gotta remember her for the blunder bus
 
More importantly, who over the age of 16 would say something that retarded?

It sounds like a virally marketed line from a Judd Apatow movie.

"Let's see how many stupid-ass quotes we can get teens and unemployed suburban males to use on a daily basis by getting them highly rated on Urban Dictionary before the movie comes out!"-Seth Rogan
 
From the urban dictionary:

blunder bus :A blunder bus is where you masturbate. Taking a ride on the blunder bus is masturbating, and a Bus Movie is someone attractive that you think about while doing so.
That girl is real bus movie material, I gotta remember her for the blunder bus

Wow, you're good. I wouldn't have gotten that in a million years.

There is a "special bus" joke in there somewhere, I just know it.

Oh, I doubt that but I know there's a Shortbus joke.