I have used two hairs for particles by whipping one to the bend and one from the eye. If you make sure that they are not too long then they won't come into contact with each other. I have also used two hairs for boilies. In this instance whip a long hair halfway down the shank but leave the both tag ends long. Tie a loop at both ends. Using a line aligner made from shrink tube, before shrinking thread the upper tag end up through the tube and out of the very top. The main line shoud exit the line aligner about three quarters of the way up the tubing in front of the eye. Using a pop-up on the bottom loop and a bottom bait on the upper loop, it creates a very difficult rig for a carp to eject as the two separate baits move about in the mouth. If you encase the rig from top bait to bottom bait in rig foam, this also will prevent tangles.