So, 'gumping it' is when someone is not quite retarded, but they're like just on that line.
"I need to confess a sin, Father. I worked at a grocery store in my teenage years, I won't get specific. There was this one girl-- are you familiar with the term 'gumping it' --so while it's an ethical conundrum, it's not fucking a retarded person if you were to sleep with 'em. This will come important later in the story..."
While our lifespan is the number of years we will live, our healthspan is the number of healthy years we will have and our sexspan is is the number of years we will continue to be healthy enough to continue having an active sex life.
A lighthearted reaction upon receiving disappointing news of some sort. Usually something that isn't a particularly a big deal, esp. when it primarily affects someone else - sort of a mild schadenfreude. Sometimes doubled or tripled, and possibly said in a sing-songy voice for added comedic effect to imitate a muted trumpet, which is how the meme originated.