Bobble Head Advice?

[LauraJ]

I have a Doll Love Fuyumi head on a Fantasy Doll 1/6th body, and the head hole is a bit large. I have put a silicone washer (got it from Mint on Card) in her neck, but it tends to slip through the neck hole into her head and the bobble effect returns.

Is there any reason not to glue the silicone washer to the neck well of her head. It fits so nicely when it is there, and I just want to figure out a way to stop it from slipping inside and making poor Robin a bobble head.

Thanks in advance.