Since you guys are really hitting it off, if he's a real friend and a good man he'll hear you saying "Hey man, can you not put me in choke holds? I'm not very comfortable with people touching my neck" and he'll hear you, apologize and say he won't do it again. If he's less than a good man, well, better to find that out now then when he's got you in a death grip and won't let go. =)