I have used my alts to pull 90% of the time. Mostly through staggered castsequences or just straight out abilities. Ex. Pally's Hand of Reckoning, use on alt first, then when mob gets in range of everyone, switch back over to tank/main/whoever. Hunter's arcane shot (quick, can use while moving and can use /cleartarget to get hunter to stop attacking). Lock's non-DPS curses (weakness, elements, etc). Basically, just use an ability on your alt, and the mob will stand on top of your main, and bam, everyone is in range, one melee attack and the alts won't move, and you can move your main all you want.

90% of the time, if the mob is moving, the alts will do a square-dance around the mob if you use IWT. If the mob is standing still, IWT works normally (alts walk up and bash faces in). So, maybe if you screw up and pull with your main, stand still and then push IWT and your alts will probably walk up normally to the mob instead of dancing with it.