Ours inflated fine. I also too thought it was going to pop. Our ball is inflated to 30'' and is rather stuffed with air LOL
It looks as if its inflated fully between 22-26'' but keep on filling it up slowly from there!
Also the plug is located in a small bag that contains 1 white plug and a plastic nozzle. We found ours in the bag that contains the small ball. The small ball is just like a basket ball and does not require a plug.
TIP: put some soap on the nozzle because it is very hard to get in. Just make sure its inflated to the right size first otherwise you cant easily get it out!
