To "Cruise Line" is the act of pushing one's face in between two LARGE breasts, and rocking one's head from side to side very rapidly while making a vigorous, lip-vibrating "brrr" sound and in the process adding more power and more brr to the vibration due to the larger breast. It is recommend to use the "cruise line" on a girl with larger than a D-cup. Very close to motorboating just has to increase the scale of power.
"Did you see her rack, I just want to cruise line those puppies"
by thatguydiditagain March 16, 2011