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1. butter the bagel
the process of ejaculating on the buttocks of your partner, then spread the cum all over the buttocks.
hit it doggy style (in either hole), then ejaculate on her/his ass. take your penis to butter the bagel, then reinsert into either hole.

usage:
guy to girl: yo, let me butter your bagel
girl to guy: can you butter my bagel, please?

dude#1 to dude#2 about a girl: dude, i buttered that bagel last night
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