Mom used to get this song stuck in her head....

My mom passed several years ago from early onset dementia. She used to get a specific song stuck in her head... how ever she only knew one line.... it went like

"won't you come and play with, my ding-a-ling, my ding-a-ling"

I am aware that it's a weird song, IDK why i remembered her singing it.... I am very curious what the actual lyrics are and what the song is about. She thought it was some kind of kids toy, sometimes she would think it was sexual and get all flustered and laugh at herself because she said ding-a-ling. LOL my mom was funny.

Any ways, I would appreciate the help.