Hmm, well that makes me feel sooooo much better.Now I have to ditch my pillowcase idea.
The thing is though, holding his head like that is not going to help his aggression. Its only going to make it worse. You could wear a long sleeve shirt that is made of thick material (may be a bit toasty while you feed) but that may work. And just wear gloves. (I had to do this for a ferret of mine who had a biting problem. Once she realized biting me didn't hurt me, she stopped and I could stop wearing the gloves)