straight military guy, usually Navy, who does gay "solo jerk-off" videos for gay guys for extra cash...a profitable endeavor that doesn't make them gay...just means they are confident with their packages and love getting paid money for something they usually do for free by themselves...
Ensign Hawkins earns extra spending money as a shellbacker when he's on shore leave.
by bottomboy_tj December 28, 2015
A US Navy tradition that occurs when a ship crosses the equator. Any sailor or Marine who's first time passing the equator is subjected to a hazing ritual called "Shellbacking."
When I sailed with the 15th MEU out of Camp Pendleton I got Shellbacked.
by Matt_usmc August 22, 2006
A Shellback is a Pollywog that has gone through The Crossing the Line Ceremony. Sometimes referred to as Sons of Neptune.
I became a shellback when we crossed the line on our way to Australia.
by xNilx February 10, 2010
adj. A US Navy (and possibly other nations) tradition that occurs when a ship and it's company crosses the equator and the international dateline simultaneously. In doing so, the wog, and even plain shellbacks must go through an initiation process; an accepted form of hazing in todays military. Its should also be noted that when the dateline is crossed, you skip a day. Davey Jones Himself as well as Neptune join in on the fun as well. After all is said and done, a steel beach picnic usually follows this time honored tradition.
sailor #1- "Back in the day, when I was aboard the USS Forrestal during a WESTPAC cruise we obtained our Golden Shellback status."

sailor #2- "What's a Golden Shellback?"

sailor #1-"You're such a slimey wog!"
by Sanctimonious January 30, 2008