A blowjob. It is based on the double meaning of the following lines from California Dreaming by The Mamas and the Papas:

stopped into a church
I passed along the way
well, I got down on my knees
and I pretend to pray
Hey, so you know Katie? Yeah, she gave me a california dreamer after I bought her dinner.
by braulio009 September 21, 2009
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