Thumb Breath

What is required to type multiple sentences on to a smart phone. Or, the time one takes to type on a smart phone uses their thumb breath. If you're getting tired of typing on your phone, you're out of thumb breath.

Save your thumb breath, I'm not reading your message right now.

SYTB

Save Your Thumb Breath.

Meaning, I'm not paying attention to your text messages.

SYTB, you can't talk me out of it.