Speak Up....
My advice to you, is speak up. Especially if you're at a tickling gathering, where your fetish is understood. I assume you've been a ler at gatherings or with individuals. Mention your desire to switch or be the 'lee to someone you're tickling. I was exclusively a 'lee until someone that was tickling me, confessed he loved to be tickled himself (actually I playfully tickled his feet, and he jumped about 10 feet into the air--it wasn't hard to figure out!) Of course, how could I say no! You know what, I had a blast, and so did he. If he hadn't 'fessed up..we would have missed out on a great time! So don't be shy, especially around ticklers/lees.
Ok..that was my 2 cents
tbbw