Three options:

• Acquire the Sedona Method from a suitable source. It is particularly useful for 'releasing' that sort of stress reaction. (An audio form preferably - a text version is too much like work!)
• Read comments by pjeby, his approach includes rewiring the underlying associations that lead to the aversion. Hopefully PJ himself is following the comments at the moment!
• Don't try to work. Go and sit in a chair and think "I am writing my paper" to yourself over and over. Now here is the important part - you do NOT use the build up of willpower you get to go and force yourself to work. You hold yourself back from any attempt to make yourself work and just keep relaxing and keep thinking "I am writing my paper". You only allow yourself to go and work when you really, really want to. If this means you spend two hours relaxing instead of working then that's good too. This should be instinctively associated with productive self nurturing rather than the shame of procrastination.

That final approach would probably be better described in a post than a dense bullet point but it does work for me. In fact I'm planning to go think to myself "I am putting the entirety of my semester's work into supermemo".