How to log out of twitter from someone's iphone?

[Y Dobon]

Go to Twitter's website (http://www.twitter.com), log in and immediately change your password:

Settings > Password

then go the apps section

Settings > Apps

and revoke access for *everything* you see there.

The next time anyone tries to access your Twitter account, they will be prompted to supply a password, the new one which you changed.

In the future, it is highly advisable that you do not give out your Twitter password (or the password to any of your accounts), since you clearly do not have the knowledge on how to deny access, plus you appear to have poor judgment in selecting friends.