I can never ever ever get it to work. I start out thinking "Alright! This time I'll finally blow it up ALL THE WAY!", but as soon as the balloon necks, I get both an intense feeling of anxiety over the risk of it suddenly popping as well as an even more intense urge to tie it off and hug/cuddle it. And then I always chicken out and tie it off.
Oh well. At least I get another cuddle buddy with each failure.