My 7 month old kitten still suckles on pillows/blankets?

So, he's done this ever since we've had him, really (since he was a few days away from 2 months old.)

If there's a blanket or pillow that's fuzzy or sherpa-textured, he'll make biscuits on it and then start suckling. We've tried to stop him after a while but he just keeps doing it before wandering off somewhere to fall asleep.

I won't lie, it's pretty cute, but I figured he'd grow out of it by now. Is this something he'll do as an adult as well? Should I stop him from suckling?

He's also pretty small for 7 pounds, height/length-wise, so my husband and I figured he was the runt of his litter. We know he came to the shelter from off the street, but that's really about it, and since we adopted him before he was even 2 months, we figured him not having enough time with his mom could've been part of it. Idk?

So, he's done this ever since we've had him, really (since he was a few days away from 2 months old.)

If there's a blanket or pillow that's fuzzy or sherpa-textured, he'll make biscuits on it and then start suckling. We've tried to stop him after a while but he just keeps doing it before wandering off somewhere to fall asleep.

I won't lie, it's pretty cute, but I figured he'd grow out of it by now. Is this something he'll do as an adult as well? Should I stop him from suckling?

He's also pretty small for 7 pounds, height/length-wise, so my husband and I figured he was the runt of his litter. We know he came to the shelter from off the street, but that's really about it, and since we adopted him before he was even 2 months, we figured him not having enough time with his mom could've been part of it. Idk?