Er... to "hit on someone" means to make a pass at. You might flirt, show that you're romantically interested, ask them out, that kinda thing. Hitting on someone results in failure about 19 times out of 20. Or maybe that's just me. Er... ... ... "to get some". Well, this is about intimate gratification. Intimate means to be "close". Could be close physically, could be close in terms of being unguarded and sharing secrets, or just having a deep understanding. But in "get some" intimate means the physical kind. Gratification is about pleasure. So "getting some" can range from huggin' an' kissin' (I guess) up to... whatever you can imagine.