I'm able to hold Shade and Pixel on their backs in my hand with no issue. Piper was never a fan, I used to be able to do so with Léa as baby but she outgrew that phase and I'm not quite there trust wise with Joey and Zuri.
Petey, well I would never attempt to hold him in such a way, since this would guarantee me getting bit. For some reason, the Boy never really tried either. That is, until tonight. I'm not sure what got into him to want to try it tonight and never before, but he did, and Petey just laid there. He offered his finger for Petey to grip to flip back up once and Petey ignored it, looking rather regal on his back. The second time the Boy offered his finger though, he did take hold rather quickly.
I'm not surprise the Boy was able to do so, but I think he is and looked rather proud of himself!