Mouthstick Stylus
From: Griffin Technology

The Griffin Mouthstick is a capacitive touchscreen stylus that is designed to
be held in the mouth. Using this stylus, persons with limited or no use of
their hands can enjoy the advantages of touchscreen interfaces on smartphones
and tablet devices. $29.99

View the product at:
https://griffintechnology.com/us/products/stylus-keyboards/mouthstick-stylus

Comment by Deis Anson, MS, OTR:
"This product appears to be motivated by their association with the
Christopher Reeve Foundation, but looks like a pretty well-designed product."