Actually, I lied - I don't have DS on the duvet: we use three blankets instead. 
Interesting, Bertie, about the skin-to-skin contact thing. I find now that DS can move around a bit and away from me and it doesn't disturb me at all, although he's old enough now that it doesn't make me nervous.
I wear a vest, thick top and thick cardigan - dressing gown too if it's very cold so that my top half doesn't get cold (the blankets stop just under breast height for me). Because DS doesn't just latch himself on, I can zip the cardigan back up again after feeds.
DS sleeps in my bed before I go to bed now. When he was a bit younger he'd sleep in the cot before I went to bed, then I'd either take him into bed at my bedtime, or from his first waking after my bedtime.
On the position thing, when DS fed frequently I used to put him on my stomach and roll over to the other side each time he woke, so that I alternated sides. Now he stays on the same side of me, but he usually only feeds once a night.