Instead of saying IDK (I don't know) to a question, you can say IDKY so your friends at least have some reassurance that you're going to make the effort to answer the question in the future.
Tommy: "IDKY" (This most likely means that Tommy will eventually tell Sam whether or not they're going to hang out. In this case, Sam has the reassurance that he should get the update at some point that day.)
'Cause it's so fun to see my face starin' back at me I don't know your fuckin' name so what? let's fuck! (idkyfnswlf) all day, I dream about sex all day, I dream about fuckin'
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.