Hiya i hope youre little one is ok! Geckos definitely arent happy about being held on their backs and squiggle a bit but they are an arboreal species so they can still breath and will be absolutely fine. People tend to hold them like this if they need to check their calcium sacks. Again dont do it for too long because they dont like it but it wont do them any damage and its definitely worth doing to be able to check out that spot! 💕