v. The act of multiple friends intentionally loading the same pornographic video simultaneously from their respective computers and masturbating to said video. This is often coordinated by phone, which is commonly left on speaker throughout the video. In more serious cases, the friends will enter a video chat room with each other through services such as those provided by Skype and AIM.
Example 1:

Dylan: "Hey, man. Got any plans after class?"

Cody: "Well, not really. I'm probably just gonna go home and fap."

Dylan: "Same, bro! We should totally sync up."

Example 2:

Dakota: "Hey, guys. I found this really hot vid on the net. You guys all wanna watch it at my house tonight?"

Matt: "Hell no. That's fucking gay."

James: "Matt's right. Why don't we just sync up instead?"
by Yuletide Piirate March 28, 2010
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"Syncing up" is achieved when two males and one female participate in the sexual act of an Eiffel Tower, or a three way, and both males achieve orgasm at the exact same moment. It is a very unique situation that has to be very intricately timed in order to simultaneously ejaculate, or to sync up.
Person 1: "Hey man what's the plan for tonight? Are you hanging with Jessica?"
Person 2: "Ahh idk bro, I'm just tryna sync up with one of the boys and I'm not sure if she's down."

*person 1 and person 2 fist bump*
by Grillmasterg June 17, 2017
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