any experience with bike seats?

[sneezecake]

ds has CP and has quite a foppy trunk, I'm trying to get back into shape and have always loved riding my bike. I would love to get a little seat for ds to ride along with me. anyone with any experience with these things, how successful do you think it would be. he's also qute small about 8 kg is it possible to pad him into it?

thanks, riven, he's not entirly limp spagetti, but if he knows hes being supported by something he will flop a lot more. hes better just sitting by himself (until he forgets and tumbles)I will look into it a bit more see what physio says etc x