It depends on the two pair, top two pair is pretty good against one or two opponents and it can be alluring to slowplay. bottom two pair though, it doesnt matter how many people you are against, two small pair is vulnerable to a board pair and has fucked every one of you peeps at one point so you should never slow play it. This one tournament i called a bunch of limpers on the SB with 52 suited, flop comes 10 5 2 some douchebag slow played his KK and we got it all in on the flop, river comes a 10:P