This is one of the reasons, if when asked, "Would you be okay having twins again?" I would most certainly say "Yes."
Every night we put them to bed in their own separate beds, but when we go back in to tuck them in for the night, they are usually in one twin bed, on one pillow, surrounded by books and evidence that they fell asleep having fun. Having a built-in best friend and sleepovers every night is definitely a special perk of having a twin sister. I am so lucky to be their mom.