I always study in bed, because my desktop is on my desk so I'd be distracted all the time if I did my studying at my desk xd But most of the time I only sleep in my bed, cuz omg, the backpain when you've been laying/sitting too much on your bed.. xD
I do pretty often, though most of the time I'm not there is spent at my desk even when I'm not using the computer or drawing. TBH I'm there right now, mostly so I can leave my phone on the charger while I use it.
I have a very small house, also the bedroom, and I live in it with my brother so we live in our beds. Actually, it's a bunk bed. And there are other reasons: in the living room there are my parents so I feel umconfortable to study with them near and after a long time sitting on the school's chair I want a little comfort to study.