Tiny dacko is slang for the word small dick but is more like a more less insulting thing to say to another. Dacko is mostly said by kids from around 12-15 years old.

n. The birth name of somebody who has changed their name. Most commonly attributed to trans people, but can be attributed to any person who has changed their name. (sometimes written as two words: dead name)

v. 1. To call somebody by their deadname.
v. 2. To out somebody's deadname to the public.