Hello! I have something I've been meaning to do for several weeks now, but I just can't do it. If someone here could help me, that would be absolutely fantastic! What I would like you to do is:

1. Say that you're in.
2. Around 20 hours from now, ask me if I did the thing.
3. If not, yell at me. In a friendly (but concerned) way.

(These are guidelines, feel free to add your own touch.)