•The first author has to write the first draft, and contribute at least 50% of experimental results.

“I want to the first author, but I want my adviser or my colleague to write it….”

•Maybe a Yes, if you contribute 50% write-up from your thesis, and 50% of experimental results.
•If your adviser or colleague did all writings, clean up your mess, and contribute 50% of experimental results, then what?
•Contributions are feelings, but writing is an attitude.
•Discussing the authorship before the first draft even in a urgent circumstance.
•If you do not write, you will lose the position as the first author.