Discipline...

The past two days have been very challenging around our household. Joshua has been teething - now four teeth at once - and has the accompanying runny nose and fever. His sleep is all off. He has been waking at night or very early morning, naps are off kilter, and to make matters worse, his daddy has been working so much Joshua's only glimpse is for the 5 minute overlap in the morning before Brad rushes off and after Joshua wakes up. Bring in my child's recent desire to test boundaries, and you can see why life is a bit of a challenge these days. He learned on Monday that he could climb up on the toilet and sit on the side of the sink. He apparently loves to sit with his feet IN the sink and the water running. I have told him time and again not to do this, I remove him each time (and most of the time before he can get all the way to the top) and I have tried distraction. He has also begun to protest when I tell him "no". So, now, the question is - what to do to discipline? It is clear he needs consistent guidance and feedback, but to what do I respond and what is the appropriate response? When he laughingly goes the other way when I tell him to come, what is the appropriate discipline? When he yells when I tell him no, again, what is the appropriate discipline? I know this is one of the biggest struggles we have as parents, something every parent struggles with. Suggestions appreciated...!!!