Suffocating on stuffed animal?

my son will be 4 months old on saturday. He is a cosleeper who isn't happy sleeping with mommy anymore :( so sad. But the only time he will sleep in his crib is when i put his arm around a stuffed pooh bear the size of his upper body, i was worried if i let him do this he could suffocate in his sleep by burrying his face in the stuffed animal. there just isn't enough room in the bed anymore, he just kicks and grunts all night long :(