When the person on the performing end of fellatio quickly and thoroughly spits out the other's love juice, resembling a sprinkler system.  This is usually in response to a "surprise" attack, but not always.
Don't even think about asking Shaniqua for a blowjob, she'll go all rainbird on you.  Instead, dangle that cock-sicle in Kimberly's face.  She'll lap it all up.
by z0ner July 3, 2007
 Get the rainbirdmug.
Get the rainbirdmug. by Mr. Noyb July 31, 2008
 Get the rainbirdmug.
Get the rainbirdmug. by BreathingCompass February 6, 2010
 Get the Rainbirdmug.
Get the Rainbirdmug.