When someone jumps the gun during an attempt to synchronize cracking open cans of soda or beer... therefore ruining the massive head-turning "clack" sound you were all hoping to create.
question: "Dude! what happened there? We were going to crack-open on the count of 3"
response: "Sorry man... I've been having trouble with premature eclackulation lately"
When you fast forward through the commercial on your DVR and stop short before the commercial is finished in anticipation of the commercial being over.
I got a little excited and experienced premature clickulation when I was watching TV last night so I saw the ends of all the commercials.
When I was fast forwarding my DVR I had some premature clickulation... the commercial wasn't finished when I was!