DS is really irritating me at the moment with his messing around and refusal to follow instructions properly. He seems to do it especially when we're in a rush too and I get so frustrated, so I need a strategy here!
An example is: I ask him to get dressed, he refuses to do it himself (he definitely can) and insists I help him, then he jumps on his bed, or dances around in a circle, or lies around in all sorts of unhelpful positions and puts on a silly voice saying "I can't move. I'm too tired." if I try to get him to sit/stand still so I can actually put his clothes on. It takes forever, and I get really irritated and usually end up shouting or saying "Fine, do it yourself then!" which just makes him cry and he still doesn't even do it so I end up helping him 5 minutes later 
It's not just getting dressed though, it's anything I'm trying to get him to do, and it's totally random. An instruction he'll follow without question one day is met with raspberries and silliness the next. And he tries to sidetrack me and it often works
which is another issue I suppose - how to teach him to focus when I'm not especially focused myself 