The downside of keeping your head that low,and this is why I highly recomend knowing who your fighting,if he has a quick hard uppercut he's taking your head clean off
Try to get in to a little arm dance when he tries to hold,little circles while maintaining contact if you dont want to hold with him.If he is holding you can still get shots off tot he back and to the back of his head.They arent legal and they wont have that much on them but it may make him regret holding so damned much.Another thing you can do,is when you have him there is lean,hard on the shoulder with your chin,find his collar bone and grind hard on it with your chin.