that sounds like you've overcarbed the beer, and all the co2 is breaking out of solution when you pour.
honestly, i feel the best way to force carbonate is to leave it at your desired volumes of co2, and leave it. if you try to shake it, you won't know how much co2 has dissolved into the beer, and you will be drinking it green anyway, which to me is a waste of beer.
if you really want to carb it quickly and to the proper volumes of co2, you need a diffusion stone. it is what i use to carb my sodas quickly, as they are from concentrates and don't need any aging, and for oxygenating my wort with industrial oxygen. i'll use it to force carb a beer if i need to, particularly if i am trying to do it at room temp, but i prefer to just set it and leave it for a couple weeks.
if your beer is pouring wrong, and you did the shake at high psi method, you need to get a 'gas bleeder valve'
let your beer stabilize at your serving temp, don't hook up any gas for a day or so. after a day, put this on a QD, and hook it up to the keg. find out what pressure is in the head space. if the beer has equalized, you should be able to know how many volumes of co2 are in the beer. if it is too high, you need to start bleeding off excess pressure from the keg.