Holding my chin

Hello,
I have a 5 month old hetro beige chinchilla, and he is very social he loves to jump on my arms when I interact with him while he is in his cage but I haven't been able to pick him up on my own, and when he jumps on my arms I can't hold him because he jumps off when I try it and I cant let him sit on just my hands without holding him because he can jump of at a bad time and get hurt or escape. I really want to be able to pick him up for emergencies and to let him out for playtime, but I tried scooping him up but he jumps away then and I've tried to get him to get used to the feeling of a hand on his belly while petting him and he is okay when I pet his belly but when I try to pick him up like that so I can also support his bottom legs he makes a noice and jumps away. I am really clueless as what I can try because I do want to be able to pick him up if needed. Thank you in advance!