with just 1 baby, i do get attention already.
with twins, you will get even more! because the chances of twins are very little. that's y it's so rare that it amuses people. it will naturally make people curious.
if you find it tiring to answer the same question from different strangers, make up answers for your own amusement.
if they ask you are they twins, then you can answer '1 is my son. the other 1 is my husband's brother's aunt's neice-in-law. (which is still you)'. make them confuse and see their reaction.
i think you can't avoid. because personally i'm curious too. if i see twins, the most i'll nudge my husband, point a bit and give a few more glances to see how cute or similar they are. i won't try to ask the mummy any questions.