Backpacking Dog

Here's Isaac, seachring for bits of ham I've hidden around the living room (one of his favorite games) while wearing his new backpack. I need to adjust the straps, they are too loose and it's sliding to one side. He was not cooperating when I was trying to get it on him. He kept pouncing on toys and then rolling over for a belly rub. He only had it on for about five minutes anyway, while he was finding his ham. I want him to get used to wearing it, so he will only wear it for very short periods at first and while doing his favorite activities.