The first set of poi i bought had tails and i ran into this problem. they are quite dooable though dont worry! Is it the heads that colide or just the tails? Try really exaggerating an up and down motion with your wrists as that should force the poi to stay in the wall plane in front of you. also try and slow it diwn and see if one poi is ending up at the wrong angle to make them tangle.bare in mind the wind really affects them so if your practicing outside try the tails off for a bit
i hope that helps a bit!
Beginners do it until they can get it right, experts do it until they can't get it wrong.
XBL Gamertag: o Lawliet o