Exactly what its name implies. Someone's had a bit too much; someone's telling a bit too much.
1) Post with your character. Name and canon go in the subject line.
2) Include somewhere, be it the subject line or in the text itself, if your character is going to be confessing or confessed to. Or open to both options.
3) That's it. Everything else is up to you. How they confess (in person, on the phone, over text) and what they confess is all up to you. No RNG here.
4) Have fun.