Probably you will be helped by setting a TwitterOAuth instance itself into the session.
<?php
// Make sure to load library before starting session
require_once('twitteroauth.php');
session_start();
if (isset(
$_SESSION['oauth_token'],
$_SESSION['oauth_token_secret'],
$_GET['oauth_verifier']
)) {
// TwitterOAuth instance, with two new parameters we got in twitter_login.php
$twitteroauth = new TwitterOAuth('CONSUMER_KEY', 'CONSUMER_SECRET', $_SESSION['oauth_token'], $_SESSION['oauth_token_secret']);
// Let's request the access token
$twitteroauth->getAccessToken($_GET['oauth_verifier']);
// Save TwitterOAuth instance in a session var
$_SESSION['twitteroauth'] = $twitteroauth;
// Reset parameters
unset($_SESSION['oauth_token'], $_SESSION['oauth_token_secret']);
} elseif (isset($_SESSION['twitteroauth'])) {
$twitteroauth = $_SESSION['twitteroauth'];
} else {
die('Error');
}
// You can request here using $twitteroauth.