As happy as a sandboy is an expression which implies blissful contentment and comes from the days when Publicans in the 17th-19th Century used to spread sand on bar floors to catch slops, spills, spit and so on. They used little boys ie Sandboys, to spread sand on the floor & sweep up the soiled sand. They were 'paid' in ale, normally the slops, which made them drunk/merry/happy.
Nickname given to bales of marijuana thrown overboard or out of airplanes. Origin is reportedly from members of the USCoast Guard in the area of Southern Florida.
"Base we've got some square groupers floating outside of Miami harbor."
A sunburn or suntan focused on the left arm. It is caused by the left side of the body being the only half that gets exposed to sunlight while driving. Presumably, it would be located on the right side of the body in countries where they drive on the left side of the road.
I had a trucker's tan after driving for 10 straight hours on a sunny day.