hesitype 

Hesitype is when you hesitate while typing a message, either text message or instant messenger. The person on the receiving end may see you actively typing but they never receive the message. It is often caused by lack of confidence in what to say.

She knew that I saw her text because she could see me hesitype a response.

hesitype by William Goldstein June 2, 2016

hesityping 

(n) The act of repeatedly typing partial or full phrases into a messaging system, only to delete or edit them repeatedly, often resulting in nothing being sent at all.

I kept seeing "..." but he never sent anything...shy boy was hesityping all night.

hesityping by PhoebusQ May 19, 2018