Before you start to wear make sure you are in his company and make sure you convey to your other friends how tiresome his behaviour is to you and that if it wasn't for their friendship you would have walked away ages ago.
This will ensure that they know how you feel and probably they feel the same way also so could provide good back up to you.
As soon as he makes any move towards you put your hand up with your palm facing him and calmly tell him that if he ever so much as thinks he can touch you or come into your personal space you will rip his head off.
Be very firm and calm in your tone and keep constant eye contact.
And if he has no brains at all and makes his move then simply with all the energy you can muster head butt him squarley on the nose and follow up with a good sound beating, i will gaurantee that you will have no more trouble from this ass wipe!