The mexican sack lunch is making use of your condoms in more ways then one. After ejaculating in a proflactic during anal penetracion tie it off carefully so not to spill. Take the tied up condom and give it to a friend so they may savor the love at another date. No refridgeration nessesary.
A portable toilet, or pot-o-pot, that is totally dirty, stinky, foul and fucked up and destroyed on the inside, especially on a construction site with many workers. This term comes from the massive amounts of Mexicans on these job sites, and the unsanitary conditions left by them after eating several bean sandwiches for lunch, and standing on the seat instead of either sitting, or using the U.F.O. position, in other words, hovering.
Charles- Man I've had to take a shit for hours, but I can't hold it any longer.
Dave- It sucks to be you, there's no bathrooms around,I guess you're gonna have to use the Mexican Lunchbox.
Charles- Fuck that! I'd rather shit myself! I went in there to piss this morning and it looked like someone was finger painting with a melted Snickers bar!