Bottom jaw sagging?

Hello! I am currently making a poodle fursuit and it's going along nicely except for one thing, the jaw is just too darn floppy!I wanted to make it so that it was partially open so I could drink water inside of it so I attached a jaw I made to a foam wedge to make it able to be attached to the chin but I think it's the weight of it or something but it just looks really silly! I know that not everything can be perfect but this is bothering me a great deal. I thought of putting something beneath the chin to keep it up but I tried and I couldn't make it look natural and foam lacked the strength to keep it up. I thought about sewing the top and bottom jaw together but I was worried about the thread breaking when I was fursuiting or it even burning @_@ has anyone else encountered this problem? It isn't a moveable jaw or anything, also.
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once again thanks if you reply and sorry if I didn't get the livejournal cut right I'm still quite new to making posts, sorry ~v~'