[Rivière]

To be honest I'm quite similar. I find it hard to imagine anywhere but in my bed. When I went to a stress and depression management course at the hospital, they taught us to practice mindfulness by listening to the sounds around us. Another technique on top of that was to place one hand on the chest, and the other on the diaphragm and see which rises first. Apparently when we're born, we breath first from the diaphragm, and then the lungs (which sounds backwards to me but hey ho). By focusing on seeing which rises first, we can determine how to control our breathing.

Personally I tend to just lie there and sometimes when it's so dark, I see those weird funny colours in my eyes sometimes (kind of like when you press on your eyes too much and it looks weird) and focus on the patterns generated by it.