I did try pouring water in me with a bottle like that without additional changes in the bottle itself. Well the bottle distorted and water went everywhere than in me. Nothing really happened.
-I think as long as that thing of yours is clean there should be no problem.
-And you shouldn't get the water in with much pressure by squeezing it quick.
Anyway I'm not an expert either. So you should hear out what other people have to say about it.