how can i stop my magsafe2 power unplugging when on my lap?

Currently working for about 8-10hours a day for uni on my mac air on my lap on the couch and i'm getting to a point of exasperation with the plug coming unhitched everytime i move - the screen dims etc. it also means i have to use the lap top in a slightly awkward position so the cord is out of the way.

Surely I'm not the first to note this frustration? Has someone invented a solution? I checked the apple store for an adapter, but no luck.

all suggestions welcome (preferably something more pragmatic than gaff-tape 🙂)