To engage in an intense exercise or fitness regime which causes one to ignore relationships and responsibilities; usually a short-lived affair seen at the beginning of the year and immediately prior to bikini season.
Jessica: "Sorry I didn't call you back. I was on the treadmill. I love the way I feel now that I'm losing weight!"
Martin: "Well, I swear to God, if you don't answer the phone again because you're stairmasterbating I'm going to come over and poke Rocky Road down your throat."
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.