[souffle]

I was just about to suggest he is spout chewing!
You need to take the bottle off and just use a bowl for now. He will be taking in too much water spout chewing. You could try to dangle the bottle from the roof to try as they can't get a grip to chew it that way but can still lick to drink usually. You can loop an elastic band round the bottle then attach by a string to the roof.
Moving the bottle higher or lower or to a different spot sometimes works too. What we do is use a bowl only for at least 4 weeks. Next add the bottle back but only during the day when they just get up for a quick drink. If that goes well leave it in till you go to bed then off overnight. (you still keep the bowl during these times of course) Eventually hopefully the bottle can move back permanently. Try clipping a wooden clothes peg for him to chew on. Easy to replace and safe to chew! It's really important to stop this as the extra water will strain the kidneys and also change the blood chemistry washing out the good stuff and he could become ill.