To hit the acceleration pedal (or, in the US, gas pedal) to such extremities that it is parallel to the floor of a car. i.e. Hit maximum speed as quickly as physically possible.

A person who doesn't realize they are transgender yet, or is in denial; an undeveloped transgender person. When they realize, it's referred to as the "egg cracking."

Go... now! to speed up and be atentive in traffic on the road and highway

Pressing the gas pedal to the ground of the vehicle you are driving... mainley used in older vehicles, or Dodge's. Also can be used at the end of every sentence you say, just as a period would be.

laughing so hard that you just fall on the floor and “floor it”.

The act of deficating on the floor. Typcially as a practical joke at a place of buisiness.