Where to draw the line?

[Teh1337zor]

I was playing some 2/5 NL and there is a 20 dollar raise before me from the CO, I looked down on the button to see a nice pair of kings. I repop it to 60 and CO tanks. I mean really tanks, as in 10 minutes of shuffling his chips tanks. Now I'm fine with this when somebody has a decision but when I called I found he had aces. When I asked why he did it he said he wanted to disguise his hand. I can sympathize but where do you cross the line from disguising your hand and not giving off any tells to showing a complete lack of ediquite. I know I certainly dont do this, if I have a play thats that obvious, I take about 5 seconds so its not instantaneous and make my move. What are your thoughts?