It got its name from the song Mr. Bojangles:
"I knew a man Bojangles and he danced for you ..."
Check out the Bojangles on that guy!
One could also just start singing the song to alert their friends without necessarily pointing out or bringing attention to the fact you're checking out someone's package.
Normally it is spelled and said Bojangles, a fast food chicken restaruant in North and South Carolina. But you pronunced it Bohangles with a spanish flair because all the people who there are mexican and don't speak a lot of english.