Mumble

[Sarah]

To speak with the lips partly closed, so as to render the
sounds inarticulate and imperfect; to utter words in a grumbling
indistinct manner, indicating discontent or displeasure; to mutter.

[Little_Girl]

Mumble means gobbledygook or worded rubbish. A collection of letters which means nothing at all.

[Marquetta]

A sexual act in which a robed woman or gay man motorboats the scrotal sac of her male partner.

[Sarah]

Say something indistinctly and quietly, making it difficult for others to hear.