first time i used wyeast i located the inner pouch, smacked lightly but firmly, felt something break... but i could still feel the pouch inside! drove me nuts, i kept playing with it for 10 mins like an ADD cat (wait, aren't all cats ADD?), then gave up and just left it out on the counter. the pouch puffed up just fine.
turns out my smack-pack had two nutrient pouches inside it. so i burst one, but could still feel the second one.