Girlfriend fart
A fart that is extremely long and/or loud due to the fact you have been dating a new girl and cant get enough time away from her to purge your lower bowels. The massive volume is due to the constant build-up of pressure. A girlfriend fart is still considered singular if it pulsates while walking.
Dude 1: As soon as I walked out her front door, I began a fart that lasted all the way across her lawn and the sidewalk. That was like 40 feet!

Dude 2: Sounds like you have a case of the girlfriend farts my friend.

Dude 1: (farts for 32 seconds)