[user104658]

You could probably request a voluntary ban but that only amounts to the same as just not logging in, so only worth it if you don't have the willpower to just stay logged off.

As for account deletion in the sense of mass post deletion, it is possible, but it's not a standard vBulletin (the forum software) function. It should only be attempted by someone who knows what they are doing. Mass deleting an entire account causes huge problems with the database, so if someone genuinely wants all posts removed you have to do a global search and replace as a database Admin and replace them all with "..." or "post removed" or whatever, and then maybe change the username to "user removed" or similar if requested.

I had to do it for a member of the forum I used to run who was actually threatening legal action if we didn't remove everything, and it wasn't worth the hassle of fighting her on it.

It is risky though and I've seen people attempt it and have it go wrong twice. A "rogue admin" on my forum threw a hiss fit and tried to completely delete someone and messed up the entire database which had to be restored from a backup. The other (not on my own forum), hilariously, involved the Admin trying to delete a member and somehow managing to delete the "member" from the database without removing ANY of the posts, and leaving the username etched on each post as plain text rather than a user link. The result being that those posts were stuck, permanently. They had no user reference attached to them. They couldn't be altered or deleted at all other than one by one, manually, and they couldn't be searched for other than going through every single thread (on a huge forum with millions of threads) by hand. And there were thousands of them .

tl;dr - it's not a standard forum function, a database Admin COULD do it manually but it's difficult and could mess things up so they probably won't. If you ask them nicely, they might block your account and change your username to something non-specific like "removed user" but all of your posts would still be there.

Then again, there's not much point making a leaving post and then having all of your posts deleted as it would obviously go too...

My real advice would be to just log off, delete your TiBB shortcut, and not think about it again. Or maybe come back next week when your period stops.