The signature at the bottom of the emails sent from your iPhone. Your iSignature is typically changed from 'Sent from my iPhone' to something funny.
Duder 1: "So, anyway are we all going to kick it this weekend or what? I'm free Friday anytime after 7 and I'll make sure to kick my boo out so we can have dudes night. Just make sure ya'll don't drink too much because last time you tried to kiss me. You guys are such fags."

Duder 2: "I'm down. Sent from my iFuckinHateYouGuys"

Duder 3: "Nice iSignature you dick. We hate you and your iPhone too. PS: I'm down for Friday night."
by westfalia July 19, 2010
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