When you or a friend/family member is sitting in only their boxers and they get an erection. Just before the penis becomes stiff, the penis may move slightly causing the boxers to wiggle a little before it becomes a full on tent.
I was sitting eating breakfast with my dad one summer morning. It was really hot so we sat in our boxers. I was thinking about how hot the chick was on TV when all of a sudden my dad murmered "Son, you had a little boxer wiggle.... maybe you should go put some pants on?"

My face grew red as I looked down to see my still growing penis streatching out my boxers while dad just sat and laughed, pointing at my boner. I ran to my room and changed to some briefs, which conceals erections a bit better.
by Tomfapingtom July 14, 2009
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The movement of one's boxers when a male is getting an erection. The penis will shift slightly before erecting, casing a motion on the outside of the underwear.

This can occur in briefs and jocks to a lesser extent, however it is boxers that are most noticable, since there is much more room for the penis to move.
During a sleep over Bob noticed James had a boxer wiggle during their conversation about girls. He smirked as he watched James try to casualy conceal his growing erection by covering himself with his sleeping bag.
by Boxerman August 3, 2009
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When a dog, most frequently a boxer, that, when wagging it's tail, tends to also shake their entire back half off their body. Also common among labs, and girls found in Victorville, CA.
When that dog shakes its tail, its whole friggin body shakes! It must be doing the boxer wiggle!
by thomas anonymous December 28, 2009
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