Nursing logistics can be a challenge :) I prefer to nurse them one at a time (when they cooperate schedule-wise), but sometimes I can manage to nurse both at once. I use pillows and "the football hold" (a very American term :); I forget what the British nursing guides call it) and, usually, an assistant to hand me the babies and take them away again later. It's awkward but manageable.

Otherwise, I can also prop one up on my thigh and bottle-feed while the other one nurses.