fast on
adj.— «If I know I’ve got to be up early, I normally can’t sleep too well, but that night I was, as they say round they these parts, “fast on.” I was “fast on” and having a dream.» —“Alarming tale that gave me a wake-up call” by Ian McMillan Yorkshire Post (Leeds, United Kingdom) Jan. 29, 2008. (source: Double-Tongued Dictionary)
Further reading
A magnificent new book celebrates the richness and diversity of 450 years of written and spoken English in what is now the United States. It’s called The People’s Tongue, and it’s a sumptuous collection of essays, letters, poems...
If you’re ever near a sundial, step closer and look for a message. Many sundials bear haunting, poetic inscriptions about the brevity of life. Plus, language development in toddlers: why and how little ones pick up the exclamation Uh-oh...