I think only people on your friends list can ask to pick you up and you would have to be the smallest you can be so it doesn't look weird when an adult picks up an adult.
Then everyone who RP-carries you will have to add you. I don't like that idea. As for the size bit, that seems great.
Maybe you could have two separate lists, one for friends and one for people who can carry you.
I like the idea where you can have a seperate list,that way pups and cubs are safe from impersonating mum/dads
But I sort of like the wing idea.It my best useful for those baby bird rpers,or baby winged wolf rpers.And Fantasyna,lets just say for now you can only pick up people smaller than you
There is a problem there.Let's say you are a pup/cub.And someone eventually accepts your request so you can carry him/her.A pup/cub carrying an adult around,or a pup/cub carrying another pup/cub in his mouth!Must be a strong little fellow.