Well, I once had my 4 feet, 3 inch 1000 geam corn Perseus around my neck and he did not want to be taken off, so he squeezed a bit and I did not feel very comfortable about it. I did know I would win if I'd be ready to hurt him a bit.... so I think up until his strength it might be doable, unless you are below average strong in your arms.
My butter '05 corn is the only young snake that likes to hang around my neck, the others take off to the floor or end up resting comfy in the hood of my sweater if I wear one. Only the carpet python thinks he is a bracelet.
All of my adult snakes just want to explore anything except my body...
I have never felt an boa or python around my neck, but I do know how my 1 year old carpet python feels around my wrist and I will surely try to figure out first how strong she is when adult, before draping her around my neck.