The nickname given to any member of a sports team who neglects to wear fitting boxers or compression shorts and proceeds to participaate in jumping
jacks. Their neglecence results in a the very noticable flopping
motion of their
package as they continue jumping.
You: yo man aint u trippin about forgetting ur compression shorts for practice
Friend: na its
aight dude I'll just wear these loose boxers
You: But we doin jumpin jacks right now,
dude ur dick is floppin everywhere. Ur a wacker jacks forreal