How do you trick a GUY into letting you tickle the soles of their barefeet?

Interesting question. I have a very evil ex-gf who loves prolonged scenes and on more than a couple of occasions , I have been literally tortured until broken under the guise of wild . Unfortunately, though ticklish everywhere, my feet are excruciatingly sensitive. You'll have to contact me to get the full blown humbling tales....Plus, I have some very creative ways your friend can trap his feet....